5. Managing Storage

Robin discovers disks attached to the nodes and uses them for providing storage to applications. This applies to local disks, cloud volumes, and SAN stoage that are available to nodes which have the storage role assigned to them. During the process Robin collects all the required metadata about the disks and identifies them as HDD, SSD or NVMes. All the elligible disks (this excludes disks with parititions and/or without WWNs) are marked as Robin storage.

Cloud volumes like EBS volumes on AWS and Persistent disks on GCP are not physically tied to a cloud compute instance. They can be detached from one cloud compute instance and attached to another instance at any time. Logical Units from a Storage Array Network can similarly be visible from multiple physical servers in the same storage fabric or network. Robin assigns a primary host for these devices and ensures that all IO access to a device only happens through one server at a given time. As with local disks, these devices are automatically discovered by Robin and registered. However they are considered to be re-attachable given their properties. Robin makes sure these re-attachable disks are always accessible even in the event of node failure. When a node goes down, Robin detaches the disk from failed node and attaches it to a healthy node so that application data remains accessible.

Note

Whilst installing if it is known that certain disks will not have a WWN, the --set-uuid option can be provided via the installer alongside a list of disks on which there is no WWN. This in turn will result in Robin stamping a UUID on the disk and thus enabling it to be used as Robin storage.

Robin allows multiple operations, detailed below, to be performed on registered disks.

robin disk attach

Attach an existing disk

robin disk detach

Detach a registered disk

robin disk create

Provision and attach a cloud disk

robin disk list

List disks

robin disk info

Display detailed information about a disk

robin disk evacuate

Evacuate allocations off a disk

robin disk unregister

Unregister a disk

robin disk remove

Delete a disk

robin disk update

Update the attributes of a disk

robin disk unfault

Unfault a disk

5.1. Attaching a disk

If a disk was previously detached from a host due to the host undergoing decommissioning or to rebalance the storage available on the cluster one will need to attach the disk back to another host in the cluster. Issue the following command to do so:

Note

This command is only for supported for re-attachable disks. Moreover if a host became unreachable Robin will automatically detach the disk and choose a new server to reattach it to based on the accessibility of the disk and the load on the other servers.

# robin disk attach <wwn>
                    --hostname <hostname>
                    --force
                    --mount-path <mount_path>

wwn

WWN of disk to attach

--hostname <hostname>

Name of host to attach disk to. Note this is a mandatory parameter.

--force

Forcibly re-attach a disk that is already ONLINE

--mount-path <mount_path>

Specify the mount path of the disk to be attached. Note this option is only valid for AWS disks and the specified path must start with ‘/dev/sd’.

Example:

# robin disk detach 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --wait
Job:  187 Name: DiskAttach     State: VALIDATED       Error: 0
Job:  187 Name: DiskAttach     State: WAITING         Error: 0
Job:  187 Name: DiskAttach     State: FINALIZED       Error: 0
Job:  187 Name: DiskAttach     State: COMPLETED       Error: 0

Attaches a disk, which might have previously been detached due to the host undergoing decommissioning or a rebalancing of storage disks, to a particular host.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: attach - This mandatory field within the payload specifies that the attach operation is to be performed.

  • hostname: <hostname> - Utilizing this parameter results in the disk being attached to the specified host.

  • force: true - Utilizing this parameter enables one to force re-attach an ONLINE disk.

  • mount_path: <mount_path> - Utilizing this parameter results in the given disk being mounted at the path specified. Note this option is only valid for AWS disks and the specified path must start with ‘/dev/sd’.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 128
}

5.2. Detaching a disk

If a physical host is temporarily or permanently taken down and one can detach its storage disks to ensure future access. Issue the following command to do so:

Note

This command is only for supported for re-attachable disks.

# robin disk detach <wwn>
                    --hostname <hostname>
                    --force

wwn

WWN of disk to detach

--hostname <hostname>

Name of host to which disk is attached to. Note this is an optional parameter

--force

Forcibly detach a disk that is currently ONLINE

Example:

# robin disk detach 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --wait
Job:  187 Name: DiskDetach     State: VALIDATED       Error: 0
Job:  187 Name: DiskDetach     State: WAITING         Error: 0
Job:  187 Name: DiskDetach     State: FINALIZED       Error: 0
Job:  187 Name: DiskDetach     State: COMPLETED       Error: 0

Detaches a disk from a host.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: detach - This mandatory field within the payload specifies that the detach operation is to be performed.

  • hostname: <hostname> - Utilizing this parameter results in the disk being detached from the specified host. This is optional as the host to which the disk is attached can be discovered implicitly.

  • force: true - Utilizing this parameter enables one to force detach an ONLINE disk.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 130
}

5.3. Provisioning a disk

Robin provides a utility through which it can provision disks of any size, attach them to hosts and discover them automatically on multiple cloud platforms. This enables users to expand the storage available for their cluster with convenience and ease. Detailed below are the general options for the robin drive create command, followed by specific examples for each supported cloud environment.

# robin disk create <hostname>
                    --type <type>
                    --number <number>
                    --size <size>
                    --iops <iops>
                    --mount-path <mount_path>

hostname

Name of host to attach disk to after creation

--type <type>

Type of disks. Choices for GCP include: pd-ssd, pd-standard. Choices for AWS include: gp2, io1, st1. Choices for Anthos include: independent-persistent. Choices for Azure include: premium, standard.

--number <number>

Number of disks to be created. The default value is 1

--size <size>

Size of disk to be created in GB. The default value is 500 GB

--iops <iops>

IOPs for AWS ‘io1’ disk type. Can be between 100-160000

--mount-path <mount_path>

Specify the mount path of the disk to be created. Note this option is only valid for AWS disks and the specified path must start with ‘/dev/sd’.

Provisions disks of any size, attaches and discovers them automatically on cloud based nodes.

End Point: /api/v3/robin_server/disks/

Method: POST

URL Parameters: None

Data Parameters:

  • hostname: <hostname> - This mandatory field within the payload specifies the host to which the provisioned disk should be attached.

  • type: <disk_type> - This mandatory field within the payload specifies the type of disk to be created. Supported types include: pd-ssd, pd-standard (for GCP); gp2, io1, st1 (for AWS); independent-persistent (for Anthos).

  • number: <num_of_disks> - This mandatory field within the payload specifies the number of disks to be created. It should be an integer value.

  • size: <size_of_disk> - This mandatory field within the payload specifies the size of the disks to be created. It should be a string. An example value is ‘200GB’.

  • iops: <iops_of_disk> - Utilizing this parameter results in disks that can handle a maximum number of IOPs equal to <iops_of_disks> being created. Note this parameter is only valid for the ‘io1’ disk type for AWS nodes.

  • mount_path: <mount_path> - Utilizing this parameter results in disk(s) created being mounted at the paths specified. Note this option is only valid for AWS disks and the specified path must start with ‘/dev/sd’.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 196
}

5.3.1. Disk Provisioning On GCP

On Google Cloud Platform, you can attach disks to your instance via the UI or Google APIs and have them discovered by Robin by running the below command:

$ robin host probe <hostname> --rediscover

In order to verify the disk has been properly detected run the following command:

# robin disk list

Finally in order to format and initialize the disk such that it is available for use by Robin, issue the following command:

# robin host add-role <hostname> storage

Note

The hostname parameter in the example commands above refer the hostname of the node where the disk is attached.

On the other hand you can utilize Robin to provision disks in GCP to use for application deployment. To create 100 GB disk in GCP, run following command:

$ robin disk create <hostname> --type <pd-standard | pd-ssd> --size 100

These disks will be attached automatically and auto discovered by Robin so they will be ready to use straightaway.

Note

Due to Robin’s advanced feature to make sure disks are always accessible, it needs the manage disks permission to be selected while deploying cluster on GCP.

5.3.2. Disk Provisioning On Google Anthos

On the Google Anthos platform, you can add disks to cluster VMs from vSphere and have them discovered by Robin by running the below command:

$ robin host probe <hostname> --rediscover

In order to verify the disk has been properly detected run the following command:

# robin disk list

Finally in order to format and initialize the disk such that it is available for use by Robin, issue the following command:

# robin host add-role <hostname> storage

Note

The hostname parameter in the example commands above refer the hostname of the node where the disk is attached.

On the other hand you can utilize Robin to provision virtual disks to use for application deployment. To create 100 GB disk for Anthos, run following command:

$ robin disk create <hostname> --type independent-persistent --size 100

These disks will be attached automatically and auto discovered by Robin so they will be ready to use straightaway.

Note

Due to Robin’s advanced feature to make sure disks are always accessible, it needs credentials, provided via Kubernetes secret, to have all cluster and disk level API privileges.

5.3.3. Disk Provisioning On AWS

On AWS, you can attach disks to your EC2 instance via the UI or AWS CLI/APIs and have them discovered by Robin by running the below command:

$ robin host probe <hostname> --rediscover

In order to verify the disk has been properly detected run the following command:

# robin disk list

Finally in order to format and initialize the disk such that it is available for use by Robin, issue the following command:

# robin host add-role <hostname> storage

Note

The hostname parameter in the example commands above refer the hostname of the node where the disk is attached.

On the other hand you can utilize Robin to provision disks in AWS to use for application deployment. To create 100 GB disk in AWS, run following command:

$ robin disk create <hostname> --type <gp2 | io1 | st1> --size 100

These disks will be attached automatically to the EC2 instances and auto discovered by Robin so they will be ready to use straightaway.

Note

Due to Robin’s advanced feature to make sure disks are always accessible, IAM Profiles associated with the host (or permissions granted to a user) must contain all Volume write and list actions.

5.3.4. Disk Provisioning On Azure

On Azure, you can attach disks to your Azure Virtual Machines via the UI or Azure CLI/APIs and have them discovered by Robin by running the below command:

$ robin host probe <hostname> --rediscover

In order to verify the disk has been properly detected run the following command:

# robin disk list

Finally in order to format and initialize the disk such that it is available for use by Robin, issue the following command:

# robin host add-role <hostname> storage

Note

The hostname parameter in the example commands above refer the hostname of the node where the disk is attached.

On the other hand you can utilize Robin to provision disks in Azure to use for application deployment. To create 100 GB disk in Azure, run following command:

$ robin disk create <hostname> --type <premium | standard> --size 100

These disks will be attached automatically to the Azure Virtual Machines and auto discovered by Robin so they will be ready to use straightaway.

Note

Due to Robin’s advanced feature to make sure disks are always accessible, the Azure role(s) assigned to the user, whom the deployed virtual machines are associated with, must allow for management of data disks.

5.4. Listing all disks

In order to view all disks currently present on the cluster and some additional details such as the number of volumes allocated from each, their size, media type etc, issue the following command:

# robin disk list --host <hostname>
                  --role <role>
                  --media <media>
                  --reattachable
                  --eligible
                  --tags
                  --json

--host <hostname>

Filter list by hostname

--role <role>

Filter list by role. Valid choices include: all, storage, rootdisk and reserved

--media <media>

Filter list by media type. Valid choices include: HDD and SSD

--reattachable

Filter list to only display reattachable disks

--eligible

Filter list to only display disks that have free capacity and have not reached the maximum volume count

--tags

Display tags for each disk

--json

Output in JSON

Example:

# robin disk list
ID | WWN                                       | Host    | Path /dev/disk/by-id                          | Size(GB) | Movable | Type | Free/Max(GB) | Vols | Role    | Status | LastOpr
---+-------------------------------------------+---------+-----------------------------------------------+----------+---------+------+--------------+------+---------+--------+---------
1  | 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b | vnode36 | scsi-0QEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b | 50       | N       | HDD  | 38/38 (100%) | 0/10 | Storage | ONLINE | READY
2  | 0xQEMU_QEMU_HARDDISK_f12b1f33-8b71-4a8c-a | vnode36 | scsi-0QEMU_QEMU_HARDDISK_f12b1f33-8b71-4a8c-a | 50       | N       | HDD  | 28/38 (74%)  | 1/10 | Storage | ONLINE | READY
3  | 0xQEMU_QEMU_HARDDISK_e54d6149-0a4e-48ce-b | vnode88 | scsi-0QEMU_QEMU_HARDDISK_e54d6149-0a4e-48ce-b | 100      | N       | HDD  | 77/77 (100%) | 0/10 | Storage | ONLINE | READY
4  | 0xQEMU_QEMU_HARDDISK_89fc0488-2050-4f44-a | vnode88 | scsi-0QEMU_QEMU_HARDDISK_89fc0488-2050-4f44-a | 100      | N       | HDD  | 63/77 (82%)  | 2/10 | Storage | ONLINE | READY
5  | 0xQEMU_QEMU_HARDDISK_19f9ac67-5e7e-4f00-8 | vnode89 | scsi-0QEMU_QEMU_HARDDISK_19f9ac67-5e7e-4f00-8 | 100      | N       | HDD  | 77/77 (100%) | 0/10 | Storage | ONLINE | READY
6  | 0xQEMU_QEMU_HARDDISK_d523b7f2-eba7-4edc-b | vnode89 | scsi-0QEMU_QEMU_HARDDISK_d523b7f2-eba7-4edc-b | 100      | N       | HDD  | 77/77 (100%) | 0/10 | Storage | ONLINE | READY

Returns all disks currently present on the cluster and some additional details such as the number of volumes allocated from each, their size, and media type.

End Point: /api/v5/robin_server/disks

Method: GET

URL Parameters:

  • details=tags : Utilizing this parameter results in tag information for each disk being present in the response payload.

  • host=<hostname> : Utilizing this parameter results in only disks attached to the specified host being returned.

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error)

Example Response:

Output
{
   "items":[
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"READY",
         "type":"HDD",
         "nvols":3,
         "dev":"\/dev\/sdb",
         "aslices":7,
         "stormgrid":1,
         "pused":234881024,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":77,
         "role":"Storage",
         "wwn":"0x600224804c48fd7e16c608dea0919064",
         "status":"ONLINE",
         "free_alloc_slices":68,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/scsi-3600224804c48fd7e16c608dea0919064",
         "alloc_slices":9,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":6390,
         "capacity":107374182400,
         "pfree":104287174656
      },
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"READY",
         "type":"HDD",
         "nvols":1,
         "dev":"\/dev\/sdc",
         "aslices":20,
         "stormgrid":2,
         "pused":939524096,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":77,
         "role":"Storage",
         "wwn":"0x600224803bcdafde95b1f5cd27ceb5fb",
         "status":"ONLINE",
         "free_alloc_slices":53,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/scsi-3600224803bcdafde95b1f5cd27ceb5fb",
         "alloc_slices":24,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":6390,
         "capacity":107374182400,
         "pfree":103582531584
      },
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"INIT",
         "type":"HDD",
         "nvols":0,
         "dev":"\/dev\/dm-1",
         "aslices":0,
         "stormgrid":0,
         "pused":0,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":5,
         "role":"RootDisk",
         "wwn":"0x600224801d3ac9b6650afd3280aa5898-centos-swap",
         "status":"UNKNOWN",
         "free_alloc_slices":5,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/dm-uuid-LVM-vI83PDTxV3H0dWyAXfH5ef7rxTOuYyphaFy4aq3EUo1yluonS8FG0LF16ycBrdEw",
         "alloc_slices":0,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":0,
         "capacity":8254390272,
         "pfree":0
      },
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"INIT",
         "type":"HDD",
         "nvols":0,
         "dev":"\/dev\/dm-0",
         "aslices":0,
         "stormgrid":0,
         "pused":0,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":38,
         "role":"RootDisk",
         "wwn":"0x600224801d3ac9b6650afd3280aa5898-centos-root",
         "status":"UNKNOWN",
         "free_alloc_slices":38,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/dm-uuid-LVM-vI83PDTxV3H0dWyAXfH5ef7rxTOuYyphgpZcvqGdfOKaXbEbOZzNthc6btsoSXDj",
         "alloc_slices":0,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":0,
         "capacity":53687091200,
         "pfree":0
      },
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"INIT",
         "type":"HDD",
         "nvols":0,
         "dev":"\/dev\/dm-2",
         "aslices":0,
         "stormgrid":0,
         "pused":0,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":32,
         "role":"RootDisk",
         "wwn":"0x600224801d3ac9b6650afd3280aa5898-centos-home",
         "status":"UNKNOWN",
         "free_alloc_slices":32,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/dm-uuid-LVM-vI83PDTxV3H0dWyAXfH5ef7rxTOuYyphQObDlS6eMUSpSxH5zsvyg9I5a0Gpuj5W",
         "alloc_slices":0,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":0,
         "capacity":44350570496,
         "pfree":0
      },
      {
         "node_hostname":"cscale-82-140.robinsystems.com",
         "spf":0.8,
         "state":"INIT",
         "type":"HDD",
         "nvols":0,
         "dev":"\/dev\/sda",
         "aslices":0,
         "stormgrid":0,
         "pused":0,
         "nodeid":1,
         "maintenance_mode":"DISABLED",
         "availability_zone":null,
         "max_alloc_slices":77,
         "role":"RootDisk",
         "wwn":"0x600224801d3ac9b6650afd3280aa5898",
         "status":"UNKNOWN",
         "free_alloc_slices":77,
         "lused_size":0,
         "devpath":"\/dev\/disk\/by-id\/scsi-3600224801d3ac9b6650afd3280aa5898",
         "alloc_slices":0,
         "reattachable":0,
         "max_volumes_per_disk":10,
         "protected":0,
         "slices":0,
         "capacity":107374182400,
         "pfree":0
      }
   ]
}

5.5. Show information about a specific disk

In order to view detailed information about a disk such as the breakdown of its available capacity, current allocations including the associated applications, write unit etc, issue the following command:

# robin disk info <wwn>
                  --json

wwn

WWN of disk to detach

--json

Output in JSON

Example:

# robin disk info 0xQEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8
Drive: 0xQEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8
  Id: 2
  Role: Storage
  Type: HDD
  Make: None
  Model: None
  Write Unit: 512
  Availability Zone: None
  Zone Id: 1613675775
  Path: /dev/disk/by-id/scsi-0QEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8
  Node: vnode-95-28.robinsystems.com
  Protected: No
  Reattachable: No
  State: READY
  Status: MAINTENANCE
  Maintenance: ON
  Allocations:
    Current: 15G
    Maximum: 38G
    Free: 23G
    Capacity: 50G
    Factor: 30%
    AllocScore: 83
    Physical Usage: 0.16G
    Physical Free: 48G
  Volumes: 3
    Max volumes: 10
    Max latency volumes: 2
    Max throughput volumes: 1
  Applications: 3
    file-collection-1613696655681
      Instance: file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2

          Id      | Volume Name                                                        | Workload | Size (GB)      | Allocated (GB)
          --------+--------------------------------------------------------------------+----------+----------------+----------------
          1       | file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2 | ordinary | 5              | 5


    pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d
      Instance: pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d

          Id       | Volume Name                              | Workload | Size (GB)      | Allocated (GB)
          ---------+------------------------------------------+----------+----------------+----------------
          21       | pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d | ordinary | 5              | 5

Returns detailed information about a disk such as the breakdown of its available capacity, current allocations including the associated applications and write unit.

End Point: /api/v3/robin_server/disks/<wwn>

Method: GET

URL Parameters: None

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error)

Example Response:

Output
{
   "items":[
      {
         "wwn":"0xQEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8",
         "dev":"\/dev\/sdb",
         "make":null,
         "model":null,
         "devpath":"\/dev\/disk\/by-id\/scsi-0QEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8",
         "capacity":53687091200,
         "type":"HDD",
         "role":"Storage",
         "state":"READY",
         "status":"MAINTENANCE",
         "maintenance_mode":"ON",
         "alloc_score":83,
         "slices":3190,
         "aslices":15,
         "pused":167772160,
         "pfree":51774488576,
         "nodeid":1,
         "stormgrid":2,
         "reattachable":0,
         "protected":0,
         "availability_zone":null,
         "node_hostname":"vnode-95-28.robinsystems.com",
         "reattachable_nodes":[
            [
               "vnode-95-28.robinsystems.com",
               "ONLINE"
            ]
         ],
         "reattachpolicy":{
            "id":2,
            "burst_start_time":0,
            "burst_count":0,
            "burst_interval":600,
            "restart_limit":5,
            "restarts_done":0
         },
         "zoneid":1613675775,
         "allocations":[
            {
               "name":"file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2.0.e4623953-263e-4b91-b66b-6be69ab60018",
               "slices":5,
               "volume_group":"file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2.72.1.d9d9726c-8052-48b1-b7ee-b953dbe254ff",
               "vols":[
                  {
                     "id":"1",
                     "name":"file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2",
                     "size":5368709120,
                     "state":"ONLINE",
                     "media":"HDD",
                     "workload_str":"ordinary"
                  }
               ],
               "volume":{
                  "id":"1",
                  "name":"file-collection-1613696655681.b9307d9d-f1fe-4731-a815-99800f3811a2",
                  "size":5368709120,
                  "state":"ONLINE",
                  "media":"HDD",
                  "workload_str":"ordinary"
               }
            },
            {
               "name":"pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d.0",
               "slices":5,
               "volume_group":"pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d.72.1",
               "vols":[
                  {
                     "id":"21",
                     "name":"pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d",
                     "size":5368709120,
                     "state":"ONLINE",
                     "media":"HDD",
                     "workload_str":"ordinary"
                  }
               ],
               "volume":{
                  "id":"21",
                  "name":"pvc-9369013d-cba4-41a9-b9b8-15228e5ea09d",
                  "size":5368709120,
                  "state":"ONLINE",
                  "media":"HDD",
                  "workload_str":"ordinary"
               }
            },
            {
               "name":"pvc-71561296-4699-4b79-bf92-3dd5470929cb.0",
               "slices":5,
               "volume_group":"pvc-71561296-4699-4b79-bf92-3dd5470929cb.72.1",
               "vols":[
                  {
                     "id":"22",
                     "name":"pvc-71561296-4699-4b79-bf92-3dd5470929cb",
                     "size":5368709120,
                     "state":"ONLINE",
                     "media":"HDD",
                     "workload_str":"throughput"
                  }
               ],
               "volume":{
                  "id":"22",
                  "name":"pvc-71561296-4699-4b79-bf92-3dd5470929cb",
                  "size":5368709120,
                  "state":"ONLINE",
                  "media":"HDD",
                  "workload_str":"throughput"
               }
            }
         ],
         "tags":{

         },
         "max_volumes_per_disk":10,
         "max_latency_sensitive_vols_per_disk":2,
         "max_throughput_intensive_vols_per_disk":1,
         "nvols":3,
         "lused_size":0,
         "preserved":0,
         "write_unit":512
      }
   ]
}

5.6. Evacuating volumes from a disk

This command allows users to move Robin storage volumes from one disk to another. As a result, it can be utilized to free up space on a disk when it is getting full, or to move data out of a disk before it is decommissioned. To evacuate a volume, issue the following command:

Note

Robin’s placement algorithm will determine the best disks to evacuate volumes to if target disks are not specified.

# robin disk evacuate <wwn>
                      --volume <volume>
                      --to-disks <target_disks>
                      --exclude-disks <excluded_disks>

wwn

WWN of disk to evacuate

--volume <volume>

Name of volume to be evacuated. Note if not provided all the volumes will be evacuated

--to-disks <target_disks>

List of WWNs representing disks to evacuate to

--exclude-disks <excluded_disks>

List of WWNs representing disks to avoid evacuating to

--yes

Do not prompt the user for confirmation of evacuation

Example:

# robin disk evacuate 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --wait --yes
Job:   65 Name: DiskEvacuate         State: VALIDATED       Error: 0
Job:   65 Name: DiskEvacuate         State: WAITING         Error: 0
Job:   65 Name: DiskEvacuate         State: COMPLETED       Error: 0

Evacuates volumes residing on one disk to another.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: evacuate - This mandatory field within the payload specifies that the evacuate operation is to be performed.

  • volume: <volume_name> - Utilizing this parameter results in only the specified volume being evacuated from the disk. If this is not specified all volumes on the disk are evacuated.

  • target_drives: <list_of_target_drives> - Utilizing this parameter, by specifying a list of WWNs representing respective target drives, ensures the evacuated volumes will be transferred to one of the specified disks.

  • exclude_drives: <list_of_excluded_drives> - Utilizing this parameter, by specifying a list of WWNs representing respective excluded drives, ensures the evacuated volumes will not transferred to one of the specified disks.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 145
}

5.7. Unregistering a disk

In order to unregister disk from the Robin cluster due to the fact it has physically malfunctioned or it is faulted, issue the following command:

Note

A disk can only be unregistered if there are no storage volumes allocated from it and it is still attached to the node from the perspective of the platform.

# robin disk unregister <wwn>
                        --yes

wwn

WWN of disk to unregister

--yes

Do not prompt the user for confirmation of disk unregistration

Example:

# robin disk unregister 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --wait --yes
Job:   101 Name: DiskUnregister       State: VALIDATED       Error: 0
Job:   101 Name: DiskUnregister       State: WAITING         Error: 0
Job:   101 Name: DiskUnregister       State: COMPLETED       Error: 0

Unregisters a disk from the Robin cluster.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: DELETE

URL Parameters: None

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 130
}

5.8. Deleting a disk

Robin provides a utility through which it detaches and deletes disks on multiple cloud platforms. This enables users to remove the cloud storage present within their clusters with convenience and ease. One caveat is that a disk can only be removed if there are no storage volumes allocated from it. In order to remove disks via the aforementioned utility, issue the following command:

Note

This command is only valid for cloud disks.

# robin disk remove <wwn>
                    --yes

wwn

WWN of disk to remove

--yes

Do not prompt the user for confirmation of disk removal

Example:

# robin disk remove 0x087648bb1c5b68a7a --wait --yes
Job:   101 Name: DiskRemove         State: VALIDATED       Error: 0
Job:   101 Name: DiskRemove         State: WAITING         Error: 0
Job:   101 Name: DiskRemove         State: COMPLETED       Error: 0

Removes a cloud disk from the Robin cluster.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: DELETE

URL Parameters:

  • remove=true : This mandatory field within the URL indicates that the disk should be removed from the cluster.

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 134
}

5.9. Updating disk properties

In certain circumstances, due to the hardware or environmental reasons, Robin may not correctly discover all the attributes of a device correctly. As a result, in order to modify a disk properties such that they are correct, issue the following command:

# robin disk update <wwn>
                    --maxvolumes <max_volumes>
                    --maxlatencysensitivevolumes <max_latency_volumes>
                    --maxthroughputintensivevolumes <max_throughput_volumes>
                    --role <role>
                    --type <type>
                    --all
                    --set-reattachable
                    --unset-reattachable
                    --set-maintenance
                    --unset-maintenance

wwn

WWN of disk to update

--maxvolumes <max_volumes>

Max number of volumes allowed on the disk

--maxthroughputintensivevolumes <max_latency_volumes>

Max number of latency sensitive volumes allowed on the disk

--maxthroughputinstensivevolumes <max_throughput_volumes>

Max number of throughput intensive volumes allowed on the disk

--role <role>

Role of the disk to update to

--type <type>

Type of the disk to update to

--all

Run the update for all disks. Should be specified if no WWN is given

--set-reattachable

Mark the disk as re-attachable

--unset-reattachable

Mark the disk as not re-attachable

--set-maintenance

Put the disk into maintenance mode

--unset-maintenance

Remove the disk from maintenance mode

Example:

# robin disk update 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --maxvolumes 100 --type SSD --wait --yes
Job:   101 Name: DiskModify         State: VALIDATED       Error: 0
Job:   101 Name: DiskModify         State: WAITING         Error: 0
Job:   101 Name: DiskModify         State: COMPLETED       Error: 0

Modifies a disk’s discovered and/or Robin specific properties.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: update - This mandatory field within the payload specifies that the update operation is to be performed.

  • role: <role> - Utilizing this parameter results in the role of the disk being set to the value specified. Options include: Storage, Swap, RootDisk, and Reserved.

  • type: <type> - Utilizing this parameter results in the type of the disk being set to the value specified. Options include: HDD and SSD.

  • maxvolumesperdisk: <max_vols_on_disk> - Utilizing this parameter results in the maximum number of volumes allowed on the disk being set to the value specified.

  • maxlatencysensitivevolumesperdisk: <max_lat_sens_vols_on_disk> - Utilizing this parameter results in the maximum number of latency sensitive volumes allowed on the disk being set to the value specified.

  • maxthroughputintensivevolumesperdisk: <max_through_ints_vols_on_disk> - Utilizing this parameter results in the maximum number of throughput intensive volumes allowed on the disk being set to the value specified.

  • reattachable: [0,1] - Utilizing this parameter results in the reattachable attribute of the disk being set. By specifying a value of 1, the disk is said to be reattachable and vice versa for a value of 0.

  • maintenance: [0,1] - Utilizing this parameter results in the maintenance mode attribute of the disk being set. By specifying a value of 1, the disk is said to be in maintenance mode and vice versa for a value of 0.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 54
}

5.10. Unfaulting a disk

When the Robin storage stack encounters an IO error on a disk, it will mark the disk as FAULTED. Sometimes the error is NOT due to the disk, but due to environmental or other hardware errors such as controller errors. In this case one can determine that the disk is actually healthy. In turn this command allows a user to inform Robin that the disk which is presumed to be FAULTED is actually healthy and the external issues that caused the IO failure have been resolved. Robin will proceed to mark the disk as ONLINE and resume normal access to the disk. In order to an unfault a disk, issue the following command:

Note

This functionality should be used with extreme care. If the disk is actually bad, and a user utilizes this command to reverse the error reported by the Robin storage stack, it could result in data loss.

# robin disk unfault <wwn>
                     --yes

wwn

WWN of disk to unfault

--yes

Do not prompt the user for confirmation of unfaulting the drive

Example:

# robin disk unfault 0xQEMU_QEMU_HARDDISK_3c71c872-fe13-4fd5-b --wait --yes
Job:   101 Name: DiskUnfault         State: VALIDATED       Error: 0
Job:   101 Name: DiskUnfault         State: WAITING         Error: 0
Job:   101 Name: DiskUnfault         State: COMPLETED       Error: 0

Unfaults a disk that has been marked as FAULTED due to an IO error. Note this functionality should be used with extreme care and only in situations where one has determined that external issues such as hardware/controller errors, that have since been resolved, caused the IO failure. If this condition is not met, unfaulting the disk could result in data loss.

End Point: /api/v3/robin_server/disks/<disk_wwn>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: unfault - This mandatory field within the payload specifies that the unfault operation is to be performed.

  • wwn: <disk_wwn> - This mandatory field within the payload specifies the WWN of the disk on which the unfault operation should be performed on.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 187
}

5.11. Managing Volumes

A Robin volume is the unit of storage allocation from Robin storage. A volume is reflective of the PersistentVolume object within the native Kubernetes world. It provides logical storage for an application to persist data. Robin allows one to manipulate several properties of these base volumes at the time of creation including it’s replication factor (in order to avoid data loss) and the encryption/compression algorithm applied to the data stored within.

In order to aid the management of volumes, the following commands are described in this section:

robin volume list

View all volumes

robin volume info

Retrieve information about a particular volume

robin volume clone-list

List all volume clones

robin volume snapshot-list

List all volume snapshots

robin volume snapshot-space-limit

Configure snapshot space limits for a volume

5.11.1. Listing all volumes

In order to view all volumes currently present on the cluster and some additional details such as the physical usage of the volume, replica state, and mount details, issue the following command:

# robin volume list --all
                    --repl

--all

Display all volumes including those marked for deletion

--repl

Filter list to only display replicated volumes

Example:

# robin volume list
ID | Name                                                                | Media | Type    | BlockSz | Size (GB) | Used (GB) | Storage Status | SnapshotSpaceUsed (GB) | Replicas | Replica State | Compression | Encryption | Mount                                          | Marked for deletion
---+---------------------------------------------------------------------+-------+---------+---------+-----------+-----------+----------------+------------------------+----------+---------------+-------------+------------+------------------------------------------------+---------------------
1  | file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd  | HDD   | REGULAR | 4096    | 5         | 0.44      | ONLINE         | -/-                    | 2        | SYNCED        | LZ4         | NONE       | cscale-82-35.robinsystems.com:/dev/sdd MOUNTED | False
20 | mdcap-dev.engine.01.data.1.d0710617-4e5c-419a-9453-b77ea32d6a78     | HDD   | REGULAR | 4096    | 10        | 0.53      | ONLINE         | 0/0.0                  | 1        | SYNCED        | NONE        | NONE       | cscale-82-35.robinsystems.com:/dev/sdf MOUNTED | False
21 | mdcap-dev.engine.01.scripts.1.5c434f33-7e2a-421b-bc04-044d42202b75  | HDD   | REGULAR | 4096    | 10        | 0.53      | ONLINE         | 0/2                    | 1        | SYNCED        | NONE        | NONE       | cscale-82-35.robinsystems.com:/dev/sdg MOUNTED | False
22 | mdcap-dev.postgres.01.data.1.22af4bf6-12d5-4ee1-83b3-0361f15c9d13   | HDD   | REGULAR | 4096    | 10        | 1         | ONLINE         | 0/2                    | 1        | SYNCED        | NONE        | NONE       | cscale-82-35.robinsystems.com:/dev/sde MOUNTED | False
23 | mdcap-dev.playground.01.home.1.a266bca7-8169-410a-ab58-529b58d4b319 | HDD   | REGULAR | 4096    | 10        | 0.53      | ONLINE         | 0/2                    | 1        | SYNCED        | NONE        | NONE       | cscale-82-35.robinsystems.com:/dev/sdh MOUNTED | False
24 | mdcap-dev.logstore.01.data.1.3ee94e27-7368-4e77-90f3-d506a73bb29c   | HDD   | REGULAR | 4096    | 10        | 0.53      | ONLINE         | 0/20                   | 1        | SYNCED        | NONE        | NONE       | cscale-82-34.robinsystems.com:/dev/sdd MOUNTED | False
25 | mdcap-dev.nginx.01.data.1.802a6117-1dd4-4c2a-b3a7-a8b622b08ac8      | HDD   | REGULAR | 4096    | 10        | 0.53      | ONLINE         | 0/2                    | 1        | SYNCED        | NONE        | NONE       | cscale-82-34.robinsystems.com:/dev/sde MOUNTED | False

Returns all volumes currently present on the cluster and some additional details such as the physical usage of the volume, replica state, and mount details.

End Point: /api/v3/robin_server/volumes

Method: GET

URL Parameters: None

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error), 401 (Unauthorized Error)

Example Response:

Output
{
   "items":[
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.playground.01.72.1.a966a57c-8de5-4090-bed3-71d7a214c7d6",
         "volumeid":23,
         "qgroupid":23,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.playground.01.home.1.a266bca7-8169-410a-ab58-529b58d4b319",
         "snapshot_space_used":0,
         "snapshot_space_limit":2147483648,
         "active_snapshot_count":0,
         "ctime":1602802778,
         "volgroupid":23,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802778083861,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":1,
               "zonename":"default",
               "devid":4,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "nodename":"cscale-82-35.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":1,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-35.robinsystems.com",
               "mntpath":"\/dev\/sdh"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":570425344,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":2,
         "storstatus_str":"ONLINE",
         "volgroupname":"file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd.72.1.0a6b2335-0b82-4c88-815c-c47f0a7e308d",
         "volumeid":1,
         "qgroupid":1,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"LZ4",
         "lsize":5368709120,
         "name":"file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd",
         "snapshot_space_used":0,
         "snapshot_space_limit":0,
         "active_snapshot_count":0,
         "ctime":1602783389,
         "volgroupid":1,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602783389367989,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":2,
               "zonename":"default",
               "devid":2,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-3600224800aba82fe29ee8770cc6440f5",
               "nodename":"cscale-82-34.robinsystems.com"
            },
            {
               "nodeid":1,
               "zonename":"default",
               "devid":4,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "nodename":"cscale-82-35.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":1,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":1,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-35.robinsystems.com",
               "mntpath":"\/dev\/sdd"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":1,
         "vtype":0,
         "psize":469762048,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.postgres.01.72.1.c25ba799-60e1-4881-8784-ec4e0936d1da",
         "volumeid":22,
         "qgroupid":25,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.postgres.01.data.1.22af4bf6-12d5-4ee1-83b3-0361f15c9d13",
         "snapshot_space_used":0,
         "snapshot_space_limit":2147483648,
         "active_snapshot_count":0,
         "ctime":1602802778,
         "volgroupid":25,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802778074578,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":1,
               "zonename":"default",
               "devid":4,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "nodename":"cscale-82-35.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":1,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-35.robinsystems.com",
               "mntpath":"\/dev\/sde"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":1644167168,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.nginx.01.72.1.4b086eca-88c2-4168-b678-01923b1f7b3d",
         "volumeid":25,
         "qgroupid":20,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.nginx.01.data.1.802a6117-1dd4-4c2a-b3a7-a8b622b08ac8",
         "snapshot_space_used":0,
         "snapshot_space_limit":2147483648,
         "active_snapshot_count":0,
         "ctime":1602802778,
         "volgroupid":20,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802778091988,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":2,
               "zonename":"default",
               "devid":2,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-3600224800aba82fe29ee8770cc6440f5",
               "nodename":"cscale-82-34.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":2,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-34.robinsystems.com",
               "mntpath":"\/dev\/sde"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":570425344,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.engine.01.72.1.bcf3834d-9c17-463a-bf60-032c9371e4ee",
         "volumeid":20,
         "qgroupid":22,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.engine.01.data.1.d0710617-4e5c-419a-9453-b77ea32d6a78",
         "snapshot_space_used":0,
         "snapshot_space_limit":2,
         "active_snapshot_count":0,
         "ctime":1602802777,
         "volgroupid":21,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802777561630,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":1,
               "zonename":"default",
               "devid":4,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "nodename":"cscale-82-35.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":1,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-35.robinsystems.com",
               "mntpath":"\/dev\/sdf"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":570425344,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.logstore.01.72.1.f2c3a591-a34c-40fe-9277-4dd743098c19",
         "volumeid":24,
         "qgroupid":24,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.logstore.01.data.1.3ee94e27-7368-4e77-90f3-d506a73bb29c",
         "snapshot_space_used":0,
         "snapshot_space_limit":21474836480,
         "active_snapshot_count":0,
         "ctime":1602802778,
         "volgroupid":24,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802778089095,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":2,
               "zonename":"default",
               "devid":2,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-3600224800aba82fe29ee8770cc6440f5",
               "nodename":"cscale-82-34.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":2,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-34.robinsystems.com",
               "mntpath":"\/dev\/sdd"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":570425344,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      },
      {
         "media":72,
         "respoolid":1,
         "replication":1,
         "storstatus_str":"ONLINE",
         "volgroupname":"mdcap-dev.engine.01.72.1.6c3cddfa-dea8-408f-bea8-a08ec489711c",
         "volumeid":21,
         "qgroupid":21,
         "tags":[

         ],
         "rsize":10737418240,
         "slice_size":1073741824,
         "appname":"default",
         "storstatus":1,
         "current_snapshotid":1,
         "compress_str":"NONE",
         "lsize":10737418240,
         "name":"mdcap-dev.engine.01.scripts.1.5c434f33-7e2a-421b-bc04-044d42202b75",
         "snapshot_space_used":0,
         "snapshot_space_limit":2147483648,
         "active_snapshot_count":0,
         "ctime":1602802777,
         "volgroupid":22,
         "volume_ops":{
            "volops_list":[

            ]
         },
         "state":2,
         "genkey":1602802777582450,
         "fsfree":0,
         "alloc":[
            {
               "nodeid":1,
               "zonename":"default",
               "devid":4,
               "zoneid":1602807544,
               "devname":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "nodename":"cscale-82-35.robinsystems.com"
            }
         ],
         "total_snapshot_count":1,
         "status":1,
         "partitions":0,
         "fssize":0,
         "compress_algo":0,
         "asize":10737418240,
         "marked_for_deletion":false,
         "vtype_str":"REGULAR",
         "mounts":[
            {
               "nodeid":1,
               "zonename":"default",
               "state":14,
               "zoneid":1602807544,
               "readonly":0,
               "state_str":"MOUNTED",
               "nodename":"cscale-82-35.robinsystems.com",
               "mntpath":"\/dev\/sdg"
            }
         ],
         "data_state":7,
         "block_size":4096,
         "protection":0,
         "vtype":0,
         "psize":570425344,
         "resync_state":1,
         "media_str":"HDD",
         "next_backupid":1,
         "multinode_mounting":0,
         "appid":1,
         "resync_progress":100,
         "next_snapshotid":2,
         "encrypt_str":"NONE",
         "parent_alloc":[

         ],
         "cloud_psize":0,
         "encrypt_algo":0
      }
   ]
}

5.11.2. Show information about a specific volume

In order to view detailed information about a volume such as the breakdown of its available replicas, descriptions of its intrinsic properties including backing media type, encryption/compression applied etc., and tags associated with it issue the following command:

# robin volume info <name>
                    --pvc-name <pvc_name>
                    --namespace <namespace>
                    --json

name

Name of the volume to retrieve information of.

--pvc-name <pvc_name>

The name of PVC that maps to a Robin volume. Note this option can only be used if the Robin volume name is not specified.

--namespace <namespace>

Namespace the PVC is bound to. Note this option is only valid and is mandatory if the PVC name is specified.

--json

Output in JSON

Note

Either one of volume_name or pvc-name options must be specified.

Example 1 (Querying a volume via volume name):

# robin volume info file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd
Name                        : file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd
ID                          : 1
State                       : READY
Storage Status              : ONLINE
Media                       : HDD
Compression                 : LZ4
Encryption                  : NONE
Volume Type                 : REGULAR
Workload Type               : ordinary
Block Size                  : 4096
Logical Size                : 5G
Physical Size               : 448M
Cloud Tiered Size           : -
Multi Node Mounting         : False
Replica Count               : 2
Replica State               : SYNCED
QGroup ID                   : 1
Resource Pool Id            : 1
Tags                        : []
Creation Time               : 15 Oct 2020 10:36:29

Mounts:
+-------------------------------+------------+------------+---------+-----------+
| Host Name                     | Mount Path | Zone ID    | State   | Read-Only |
+-------------------------------+------------+------------+---------+-----------+
| cscale-82-35.robinsystems.com | /dev/sdd   | 1602807544 | MOUNTED | False     |
+-------------------------------+------------+------------+---------+-----------+

Allocations:
-------

Replica 1
+----+-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+
| ID | WWN                                 | Host Name                     | Devpath                                                | Allocated (GB) |
+----|-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+
| 1  | 0x3600224800aba82fe29ee8770cc6440f5 | cscale-82-34.robinsystems.com | /dev/disk/by-id/scsi-3600224800aba82fe29ee8770cc6440f5 | 5              |
+----+-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+

Replica 2
+----+-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+
| ID | WWN                                 | Host Name                     | Devpath                                                | Allocated (GB) |
+----+-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+
| 2  | 0x360022480b410ddebc69ecdea69c2bf34 | cscale-82-35.robinsystems.com | /dev/disk/by-id/scsi-360022480b410ddebc69ecdea69c2bf34 | 5              |
+----+-------------------------------------+-------------------------------+--------------------------------------------------------+----------------+

Snapshot Info:
-------
Snapshot Count              : 0
Snapshot Space Used         : 0G/-

Example 2 (Querying a volume via PVC name):

# robin volume info --pvc-name data-my-release-mysql-0 --namespace default
Name                        : pvc-35855033-3505-4dba-bf74-b8746322c528
ID                          : 6
State                       : READY
Status                      : ONLINE
Storage Status              : ONLINE
Media                       : HDD
Compression                 : NONE
Encryption                  : NONE
Volume Type                 : REGULAR
Workload Type               : ordinary
Block Size                  : 4096
Logical Size                : 8G
Physical Size               : -
Cloud Tiered Size           : -
Multi Node Mounting         : True
Replica Count               : 1
Replica State               : SYNCED
Fault Domain                : N/A
QGroup ID                   : 6
Resource Pool Id            : 1
Tags                        : []
Creation Time               : 03 Oct 2021 09:27:08

Mounts:
+-------------------------------+------------+------------+---------+-----------+
| Host Name                     | Mount Path | Zone ID    | State   | Read-Only |
+-------------------------------+------------+------------+---------+-----------+
| cscale-82-83.robinsystems.com | /dev/sde   | 1633270151 | MOUNTED | False     |
+-------------------------------+------------+------------+---------+-----------+

Allocations:
-------

Replica 1
+----+------------------------------------+-------------------------------+--------------------------------------------------------+-----------+
| ID | WWN                                | Host Name                     | Devpath                                                | Size (GB) |
+----+------------------------------------+-------------------------------+--------------------------------------------------------+-----------+
| 5  | 0x60022480a889d05f4df285d75cf253e0 | cscale-82-83.robinsystems.com | /dev/disk/by-id/scsi-360022480a889d05f4df285d75cf253e0 | 8         |
+----+------------------------------------+-------------------------------+--------------------------------------------------------+-----------+

Snapshot Info:
-------
Snapshot Count              : 0
Snapshot Space Used         : 0G/-

Returns detailed information about a volume such as the breakdown of its available replicas, descriptions of its intrinsic properties including backing media type, encryption/compression applied etc., and tags associated with it.

End Point: /api/v3/robin_server/volumes/

Method: GET

URL Parameters: None

Data Parameters:

  • name: <volume_name> - This mandatory field within the payload specifies the name of the volume for which information should be retrieved for.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error)

Example Response:

Output
{
   "items":{
      "volumeid":32,
      "resync_progress":100,
      "total_snapshot_count":1,
      "psize":503316480,
      "ctime":1615831965,
      "snapshot_space_used":0,
      "appid":1,
      "multinode_mounting":0,
      "protection":1,
      "name":"file-collection-1615831964492.12f41f8a-1cd9-451d-b719-010832f8521d",
      "snapshot_space_limit":0,
      "active_snapshot_count":0,
      "parent_alloc":[

      ],
      "status":1,
      "media":72,
      "resync_state":1,
      "next_backupid":1,
      "vtype":0,
      "current_snapshotid":1,
      "genkey":1615831965016901,
      "volgroupname":"file-collection-1615831964492.12f41f8a-1cd9-451d-b719-010832f8521d.72.1.01ceef4e-d5e9-417e-8c62-e3352d26643d",
      "appname":"default",
      "next_snapshotid":2,
      "qgroupid":1,
      "block_size":4096,
      "slice_size":1073741824,
      "compress_algo":1,
      "encrypt_algo":0,
      "tags":[

      ],
      "replication":3,
      "state":2,
      "data_state":7,
      "mounts":[
         {
            "zoneid":1613675775,
            "zonename":"default",
            "nodename":"vnode-95-28.robinsystems.com",
            "nodeid":1,
            "mntpath":"\/dev\/sdd",
            "readonly":0,
            "state":14,
            "state_str":"MOUNTED"
         }
      ],
      "partitions":0,
      "lsize":5368709120,
      "fssize":0,
      "fsfree":0,
      "volume_ops":{
         "volops_list":[

         ]
      },
      "rsize":16106127360,
      "asize":16106127360,
      "cloud_psize":0,
      "respoolid":1,
      "volgroupid":32,
      "alloc":[
         [
            {
               "id":2,
               "wwn":"0xQEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8",
               "allocation":5,
               "node":"vnode-95-28.robinsystems.com",
               "devpath":"\/dev\/disk\/by-id\/scsi-0QEMU_QEMU_HARDDISK_80cb8b56-aef2-48a8-8"
            }
         ],
         [
            {
               "id":1,
               "wwn":"0xQEMU_QEMU_HARDDISK_40b30feb-02eb-4a5a-b",
               "allocation":5,
               "node":"vnode-95-12.robinsystems.com",
               "devpath":"\/dev\/disk\/by-id\/scsi-0QEMU_QEMU_HARDDISK_40b30feb-02eb-4a5a-b"
            }
         ],
         [
            {
               "id":3,
               "wwn":"0xQEMU_QEMU_HARDDISK_50c07412-3cbb-428e-8",
               "allocation":5,
               "node":"vnode-95-83.robinsystems.com",
               "devpath":"\/dev\/disk\/by-id\/scsi-0QEMU_QEMU_HARDDISK_50c07412-3cbb-428e-8"
            }
         ]
      ],
      "storstatus":1,
      "media_str":"HDD",
      "vtype_str":"REGULAR",
      "compress_str":"LZ4",
      "encrypt_str":"NONE",
      "storstatus_str":"ONLINE",
      "storstate_str":"READY",
      "rwx_vol":false,
      "workload":0,
      "workload_str":"ordinary",
      "nfs_exports":[

      ]
   }
}

5.11.3. Listing all volume clones

In order to view all clone volumes currently present on the cluster and some additional details such as the physical usage of the volume, parent volume, and mount details, issue the following command:

# robin volume clone-list --json

--json

Output in JSON format

Example:

ID | Name                                                                | ParentSnap          | ParentVolume                                                     | Media | BlockSz | Size (GB) | Psize (GB) | Storage Status | SnapshotSpaceUsed (GB) | Replicas | Replica State | Compression | Encryption | Mount
---+---------------------------------------------------------------------+---------------------+------------------------------------------------------------------+-------+---------+-----------+------------+----------------+------------------------+----------+---------------+-------------+------------+-------------------------------------------------
9  | clone-demo.server.01.block.1.2c69deaa-52bc-40ba-b455-5271e4fae4a1   | snapshot-1603479973 | centos1.server.01.block.1.c90c49c0-74ab-4459-be69-fea9f730cc9e   | HDD   | 4096    | 1         | -          | ONLINE         | 0/0.2                  | 1        | SYNCED        | NONE        | NONE       | cscale-82-140.robinsystems.com:/dev/sdm MOUNTED
10 | clone-demo.server.01.root_fs.1.63262a2c-b8b2-4f03-9fea-65b47a95a5a8 | snapshot-1603479973 | centos1.server.01.root_fs.1.2d59b0b3-c33a-4594-9d3d-44def625a38b | HDD   | 4096    | 1         | 0.03       | ONLINE         | 0/0.2                  | 1        | SYNCED        | NONE        | NONE       | cscale-82-140.robinsystems.com:/dev/sdn MOUNTED
11 | clone-demo.server.01.data.1.dd86ccb2-ce0a-4f39-a041-66ec4d492fbc    | snapshot-1603479973 | centos1.server.01.data.1.8dec6c3f-839a-439c-b830-130386ff40f4    | HDD   | 4096    | 1         | 0.03       | ONLINE         | 0/0.2                  | 1        | SYNCED        | NONE        | NONE       | cscale-82-140.robinsystems.com:/dev/sdl MOUNTED

Returns all clone volumes currently present on the cluster and some additional details such as the physical usage of the volume, parent volume, and mount details.

End Point: /api/v3/robin_server/volumes/clone

Method: GET

URL Parameters: None

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error), 401 (Unauthorized Error)

Example Response:

Output
{
   "items":[
      {
         "qgroupid":10,
         "rsize":1073741824,
         "multinode_mounting":0,
         "volgroupname":"clone-demo.server.01.72.1.3a122025-f911-4ecf-b689-f5492bbefd72",
         "parent_volumeid":6,
         "encrypt_algo":0,
         "parent_alloc":[
            {
               "devid":1,
               "zoneid":1603415748,
               "nodeid":1
            }
         ],
         "volgroupid":9,
         "fsfree":0,
         "psize":33554432,
         "next_snapshotid":2,
         "replication":1,
         "cloud_psize":0,
         "lsize":1073741824,
         "status":1,
         "encrypt_str":"NONE",
         "volumeid":11,
         "vtype":1,
         "ctime":1603480455,
         "snapshot_space_used":0,
         "storstatus_str":"ONLINE",
         "respoolid":1,
         "marked_for_deletion":false,
         "appid":1,
         "appname":"default",
         "protection":0,
         "media":72,
         "media_str":"HDD",
         "genkey":1603480455171116,
         "next_backupid":1,
         "tags":[

         ],
         "block_size":4096,
         "asize":1073741824,
         "partitions":0,
         "parent_snapshotid":1,
         "slice_size":1073741824,
         "storstatus":1,
         "name":"clone-demo.server.01.data.1.dd86ccb2-ce0a-4f39-a041-66ec4d492fbc",
         "total_snapshot_count":1,
         "vtype_str":"CLONE",
         "alloc":[
            {
               "devid":1,
               "nodeid":1,
               "nodename":"cscale-82-140.robinsystems.com",
               "zoneid":1603415748,
               "zonename":"default",
               "devname":"\/dev\/disk\/by-id\/scsi-3600224803bcdafde95b1f5cd27ceb5fb"
            }
         ],
         "volume_ops":{
            "volops_list":[

            ]
         },
         "data_state":7,
         "mounts":[
            {
               "nodeid":1,
               "nodename":"cscale-82-140.robinsystems.com",
               "state_str":"MOUNTED",
               "state":14,
               "zoneid":1603415748,
               "zonename":"default",
               "mntpath":"\/dev\/sdl",
               "readonly":0
            }
         ],
         "parent_appname":"default",
         "active_snapshot_count":0,
         "current_snapshotid":1,
         "fssize":0,
         "parent_volumename":"centos1.server.01.data.1.8dec6c3f-839a-439c-b830-130386ff40f4",
         "compress_str":"NONE",
         "resync_state":1,
         "snapshot_space_limit":214748364,
         "resync_progress":100,
         "parent_snapshotname":"snapshot-1603479973",
         "state":2,
         "parent_appid":1,
         "compress_algo":0
      },
      {
         "qgroupid":9,
         "rsize":1073741824,
         "multinode_mounting":0,
         "volgroupname":"clone-demo.server.01.72.1.bc0f9bf3-3df2-4ec8-8a03-2edad0d4d176",
         "parent_volumeid":8,
         "encrypt_algo":0,
         "parent_alloc":[
            {
               "devid":1,
               "zoneid":1603415748,
               "nodeid":1
            }
         ],
         "volgroupid":11,
         "fsfree":0,
         "psize":33554432,
         "next_snapshotid":2,
         "replication":1,
         "cloud_psize":0,
         "lsize":1073741824,
         "status":1,
         "encrypt_str":"NONE",
         "volumeid":10,
         "vtype":1,
         "ctime":1603480455,
         "snapshot_space_used":0,
         "storstatus_str":"ONLINE",
         "respoolid":1,
         "marked_for_deletion":false,
         "appid":1,
         "appname":"default",
         "protection":0,
         "media":72,
         "media_str":"HDD",
         "genkey":1603480455157228,
         "next_backupid":1,
         "tags":[

         ],
         "block_size":4096,
         "asize":1073741824,
         "partitions":0,
         "parent_snapshotid":1,
         "slice_size":1073741824,
         "storstatus":1,
         "name":"clone-demo.server.01.root_fs.1.63262a2c-b8b2-4f03-9fea-65b47a95a5a8",
         "total_snapshot_count":1,
         "vtype_str":"CLONE",
         "alloc":[
            {
               "devid":2,
               "nodeid":1,
               "nodename":"cscale-82-140.robinsystems.com",
               "zoneid":1603415748,
               "zonename":"default",
               "devname":"\/dev\/disk\/by-id\/scsi-3600224804c48fd7e16c608dea0919064"
            }
         ],
         "volume_ops":{
            "volops_list":[

            ]
         },
         "data_state":7,
         "mounts":[
            {
               "nodeid":1,
               "nodename":"cscale-82-140.robinsystems.com",
               "state_str":"MOUNTED",
               "state":14,
               "zoneid":1603415748,
               "zonename":"default",
               "mntpath":"\/dev\/sdn",
               "readonly":0
            }
         ],
         "parent_appname":"default",
         "active_snapshot_count":0,
         "current_snapshotid":1,
         "fssize":0,
         "parent_volumename":"centos1.server.01.root_fs.1.2d59b0b3-c33a-4594-9d3d-44def625a38b",
         "compress_str":"NONE",
         "resync_state":1,
         "snapshot_space_limit":214748364,
         "resync_progress":100,
         "parent_snapshotname":"snapshot-1603479973",
         "state":2,
         "parent_appid":1,
         "compress_algo":0
      },
      {
         "qgroupid":11,
         "rsize":1073741824,
         "multinode_mounting":0,
         "volgroupname":"clone-demo.server.01.72.1.f366e12b-ae61-4f1d-a441-0258d764d5f3",
         "parent_volumeid":7,
         "encrypt_algo":0,
         "parent_alloc":[
            {
               "devid":1,
               "zoneid":1603415748,
               "nodeid":1
            }
         ],
         "volgroupid":10,
         "fsfree":0,
         "psize":0,
         "next_snapshotid":2,
         "replication":1,
         "cloud_psize":0,
         "lsize":1073741824,
         "status":1,
         "encrypt_str":"NONE",
         "volumeid":9,
         "vtype":1,
         "ctime":1603480455,
         "snapshot_space_used":0,
         "storstatus_str":"ONLINE",
         "respoolid":1,
         "marked_for_deletion":false,
         "appid":1,
         "appname":"default",
         "protection":0,
         "media":72,
         "media_str":"HDD",
         "genkey":1603480455077815,
         "next_backupid":1,
         "tags":[

         ],
         "block_size":4096,
         "asize":0,
         "partitions":0,
         "parent_snapshotid":1,
         "slice_size":1073741824,
         "storstatus":1,
         "name":"clone-demo.server.01.block.1.2c69deaa-52bc-40ba-b455-5271e4fae4a1",
         "total_snapshot_count":1,
         "vtype_str":"CLONE",
         "alloc":[

         ],
         "volume_ops":{
            "volops_list":[

            ]
         },
         "data_state":7,
         "mounts":[
            {
               "nodeid":1,
               "nodename":"cscale-82-140.robinsystems.com",
               "state_str":"MOUNTED",
               "state":14,
               "zoneid":1603415748,
               "zonename":"default",
               "mntpath":"\/dev\/sdm",
               "readonly":0
            }
         ],
         "parent_appname":"default",
         "active_snapshot_count":0,
         "current_snapshotid":1,
         "fssize":0,
         "parent_volumename":"centos1.server.01.block.1.c90c49c0-74ab-4459-be69-fea9f730cc9e",
         "compress_str":"NONE",
         "resync_state":1,
         "snapshot_space_limit":214748364,
         "resync_progress":100,
         "parent_snapshotname":"snapshot-1603479973",
         "state":2,
         "parent_appid":1,
         "compress_algo":0
      }
   ]
}

5.11.4. Listing all volume snapshots

In order to view all volume snapshots currently present on the cluster and some additional details for each snapshot such as the state, number of clones/backups that have been created etc., issue the following command:

# robin volume snapshot-list --json

--json

Output in JSON format

Example:

# robin volume snapshot-list
Snap ID | Name                | Volume                                                           | Read Only | State | ParentSnap ID | Clones | Backups | Creation Time
--------+---------------------+------------------------------------------------------------------+-----------+-------+---------------+--------+---------+---------------
1       | snapshot-1603479973 | centos1.server.01.data.1.8dec6c3f-839a-439c-b830-130386ff40f4    | True      | READY | -             | 0      | 0       | -
1       | snapshot-1603479973 | centos1.server.01.block.1.c90c49c0-74ab-4459-be69-fea9f730cc9e   | True      | READY | -             | 0      | 0       | -
1       | snapshot-1603479973 | centos1.server.01.root_fs.1.2d59b0b3-c33a-4594-9d3d-44def625a38b | True      | READY | -             | 0      | 0       | -

In order to view all volume snapshots currently present on the cluster and some additional details for each snapshot such as the state, number of clones/backups that have been created etc., issue the following command:

End Point: /api/v3/robin_server/volumes/snap

Method: GET

URL Parameters: None

Data Parameters: None

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 200

Error Response Code: 500 (Internal Server Error), 401 (Unauthorized Error)

Example Response:

Output
{
   "items":{
      "media":72,
      "respoolid":1,
      "replication":2,
      "storstatus_str":"ONLINE",
      "volgroupname":"file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd.72.1.0a6b2335-0b82-4c88-815c-c47f0a7e308d",
      "volumeid":1,
      "qgroupid":1,
      "tags":[

      ],
      "rsize":10737418240,
      "slice_size":1073741824,
      "appname":"default",
      "storstatus":1,
      "current_snapshotid":1,
      "compress_str":"LZ4",
      "lsize":5368709120,
      "name":"file-collection-1602783389182.edc29729-1bfe-4da2-87af-3e0e1fbbe8bd",
      "snapshot_space_used":0,
      "snapshot_space_limit":0,
      "active_snapshot_count":0,
      "ctime":1602783389,
      "volgroupid":1,
      "volume_ops":{
         "volops_list":[

         ]
      },
      "state":2,
      "genkey":1602783389367989,
      "fsfree":0,
      "alloc":[
         [
            {
               "devpath":"\/dev\/disk\/by-id\/scsi-3600224800aba82fe29ee8770cc6440f5",
               "node":"cscale-82-34.robinsystems.com",
               "allocation":5,
               "wwn":"0x3600224800aba82fe29ee8770cc6440f5"
            }
         ],
         [
            {
               "devpath":"\/dev\/disk\/by-id\/scsi-360022480b410ddebc69ecdea69c2bf34",
               "node":"cscale-82-35.robinsystems.com",
               "allocation":5,
               "wwn":"0x360022480b410ddebc69ecdea69c2bf34"
            }
         ]
      ],
      "total_snapshot_count":1,
      "status":1,
      "partitions":0,
      "storstate_str":"READY",
      "fssize":0,
      "compress_algo":1,
      "asize":10737418240,
      "vtype_str":"REGULAR",
      "mounts":[
         {
            "nodeid":1,
            "zonename":"default",
            "state":14,
            "zoneid":1602807544,
            "readonly":0,
            "state_str":"MOUNTED",
            "nodename":"cscale-82-35.robinsystems.com",
            "mntpath":"\/dev\/sdd"
         }
      ],
      "data_state":7,
      "block_size":4096,
      "protection":1,
      "vtype":0,
      "psize":469762048,
      "resync_state":1,
      "media_str":"HDD",
      "next_backupid":1,
      "multinode_mounting":0,
      "appid":1,
      "resync_progress":100,
      "next_snapshotid":2,
      "encrypt_str":"NONE",
      "parent_alloc":[

      ],
      "cloud_psize":0,
      "encrypt_algo":0
   }
}

5.11.5. Configure the snapshot space limit of a volume

Robin stores snapshot(s) of a volume within a dedicated space, referred to as the snapshot space of the volume. The snapshot space is considered to be a percentage of the allocated space for a volume (by default this percentage is 40%). However after the volume is provisioned the size of the snapshot might need to be modified. In order to achieve this, issue the following command:

# robin volume snapshot-space-limit <volume_name> <snapshot_space_limit>

Note

Only the snapshot space limit of individual volumes can be configured at this time. To configure the snapshot space limit for an application, update the snapshot space limit of each of the volumes it consists of.

volume_name

Name of the volume to configure the snapshot space limit for

snapshot_space_limit

Size of the snapshot space limit in bytes

Example:

# robin volume snapshot-space-limit pvc-bd01bcd9-9e4d-4a34-ac13-5a98395935b3 4G --wait
Job:  163 Name: VolumeUpdateSnapshotLimit State: PROCESSED       Error: 0
Job:  163 Name: VolumeUpdateSnapshotLimit State: FINALIZED       Error: 0
Job:  163 Name: VolumeUpdateSnapshotLimit State: COMPLETED       Error: 0

Configures the snapshot space limit of a volume.

End Point: /api/v3/robin_server/volumes/<volume_name>

Method: PUT

URL Parameters: None

Data Parameters:

  • action: snapshot_limits - This mandatory field within the payload specifies that the snapshot limit of the volume is to be modified.

  • name: <volume_name> - This mandatory field within the payload specifies the name of the volume for which the snapshot limits are to be modified.

  • snapshot_space_limit: <snap_limit> - This mandatory field within the payload specifies the size, in bytes, the snapshot space limit of the aforementioned volume should be set to.

Port: RCM Port (default value is 29442)

Headers:

  • Authorization: <auth_token> : Authorization token to identify which user is sending the request. The token can be acquired from the login API.

Success Response Code: 202

Error Response Code: 500 (Internal Server Error), 404 (Not Found Error), 401 (Unauthorized Error), 400 (Invalid API Usage Error)

Example Response:

Output
{
   "jobid": 163
}

5.12. ReadWriteMany (RWX) Volumes

Robin supports the ReadWriteMany (RWX) access mode of Persistent Volumes (PVs). An RWX PVC can be used by many Pods in the same namespace for read and write operations. For more information, see Persistent Volumes.

Robin RWX volumes are based on the shared file system. The shared file system that Robin uses is the network file system (NFS).

Note

  • Robin RWX PVC supports only helm deployment, not bundle deployment.

  • Robin RWX PVC supports non-root application Pods. For more information, see here.

5.12.1. NFS server Pod

Every RWX PVC results in an NFS export from an NFS server Pod. When you create a PVC, the NFS server Pod is created based on the demand and the configuration of NFS server creation.

Note

All Robin NFS server Pods are High Availability (HA) compliant. Robin monitors the health of the NFS server Pods and executes a failover if any NFS server Pod is offline.

There are two types of NFS server Pod.

  • Shared NFS server Pod

  • Exclusive NFS server Pod

  • Shared NFS server Pod

In a shared NFS server Pod, multiple RWX PVC exports are allocated to one NFS server Pod. The shared NFS server Pod is the default server Pod for Robin RWX PVC.

Set the default server type to a shared NFS server Pod

To set the default_server_type to a shared NFS server Pod, run the following command:

# robin config update nfs default_server_type shared

Allocate the shared NFS server Pod for PVC

To allocate the shared NFS server Pod for the PVC, use the following annotation:

robin.io/nfs-server-type: "shared"

Example

To create a shared NFS server Pod which exports 1G RWX PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-shared-1
  annotations:
   robin.io/nfs-server-type: "shared"
spec:
  accessModes:
     - ReadWriteMany
  resources:
    requests:
      storage: 1Gi
  • Exclusive NFS server Pod

In an exclusive NFS server Pod, each RWX PVC results in a dedicated NFS server Pod.

Set the default server type to an exclusive NFS server Pod

To set the default_server_type to an exclusive NFS server Pod, run the following command:

# robin config update nfs default_server_type exclusive

Allocate the exclusive NFS server Pod for PVC

To allocate the exclusive NFS server Pod for the PVC, use the following annotation:

robin.io/nfs-server-type: "exclusive"

Example

To create an exclusive NFS server Pod which exports 1G RWX PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-excl-1
  annotations:
   robin.io/nfs-server-type: "exclusive"
spec:
  accessModes:
     - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

5.12.2. Set resource limits for RWX PVC

You can set maximum and request limits for CPU and memory only for the exclusive NFS server Pods with RWX volume through the following PVC annotations.

Set limits for CPU

To set the maximum limit for CPU, use the following annotation:

robin.io/nfs-cpu-limit: <limit value>

To set the request limit for CPU, use the following annotation:

robin.io/nfs-cpu-request: <request value>

Set limits for memory

To set the maximum limit for memory, use the following annotation:

robin.io/nfs-memory-limit: <limit value>

To set the request limit for memory, use the following annotation:

robin.io/nfs-memory-request: <request value>

Example

To create an exclusive NFS server Pod with PVC annotations which exports 1G RWX PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: CSI-PVC-robin
  labels:
    app.kubernetes.io/instance: robin
    app.kubernetes.io/managed-by: robin.io
    app.kubernetes.io/name: robin
  annotations:
    robin.io/media: HDD
    robin.io/compression: LZ4
    robin.io/nfs-server-type: "exclusive"
    robin.io/nfs-cpu-limit: 300m
    robin.io/nfs-memory-limit: 300Mi
    robin.io/nfs-cpu-request: 240m
    robin.io/nfs-memory-request: 240Mi
spec:
  accessModes:
     - ReadWriteMany
  resources:
    requests:
      storage: 1Gi
  StorageClassName: robin

Note

  • The PVC annotations override the global default value.

  • You can use these PVC annotations only when you are creating a new PVC.

5.12.3. Configure NFS server Pod attributes

If you want to create an NFS server Pod other than the default configuration, you can change the NFS server Pod attributes.

The modified values are applied only to the next NFS server Pod creation. These values are not applied to the existing NFS server Pods.

View NFS server Pod attributes and values

To view the list of NFS server Pod attributes and their values, run the following command:

# robin config list nfs

NFS server Pod attributes and their values

Attribute

Default Value

Valid Value

default_server_type

shared

shared - multiple RWX PVC exports are allocated to one NFS server Pod.
exclusive - each RWX PVC results in a dedicated NFS server Pod.

excl_pod_cpu

100m

As per your requirement.

excl_pod_memory

200Mi

As per your requirement.

exclusive_pod_cpu_limit

UNLIMITED

As per your requirement.

exclusive_pod_memory_limit

UNLIMITED

As per your requirement.

failover_enabled

1

1 – to enable the failover.
0 – to disable the failover.

max_exports_per_pod

8

As per your requirement.

nfs_server_storage_affinity

none

none - an NFS server Pod is created on a node where sufficient storage and other resources are available, without checking for allocated volume.
preferred - an NFS server Pod is created on the same node as the volume is allocated. If no sufficient storage and other resources are available on the node, the NFS server Pod is created on the available node.
required - an NFS server Pod is created on the same node as the volume is allocated. If no sufficient storage and other resources are available on the node, the NFS server Pod creation fails.

pod_creation_timeout

600

As per your requirement.

service_creation_timeout

60

As per your requirement.

shared_pod_cpu

100m

As per your requirement.

shared_pod_cpu_limit

UNLIMITED

As per your requirement.

shared_pod_failover_serialized

1

1 – to enable the shared Pod failover.
0 – to disable the shared Pod failover.

shared_pod_memory

200Mi

As per your requirement.

shared_pod_memory_limit

UNLIMITED

As per your requirement.

shared_pod_placement

PACK

PACK – selects the NFS server Pod that is assigned to the most and under the max limit.
SPREAD – selects the NFS server Pod with minimum PVC assignments and ensures that all NFS server Pods are equally loaded.

Update the NFS server Pod attributes

To update the NFS server Pod attributes, run the following command:

# robin config update nfs <attribute> <valid value>

Example

To update the shared_pod_placement attribute of the NFS server Pod.

# robin config update nfs shared_pod_placement SPREAD
The 'nfs' attribute 'shared_pod_placement' has been updated

5.13. Managing Application Ephemeral Volumes

Robin CNP supports Application Ephemeral Volumes (AEVs). An AEV is non-persistent temporary storage that is attached to a Robin bundle application and consequently available on-demand for use. They are mounted inside application container(s) at a specified mount point which in turn allows the application to access the files inside the AEV filesystem. When an application is stopped or deleted the storage space used by an AEV will be reclaimed such that it can be used by other applications on the cluster. On the other hand, when an application is restarted the requested AEV(s) are provisioned again.

Note

The storage space consumed by an AEV is not reserved by a stopped application. As a result, there is no guarantee that the application will be able to restart given the fact that there might not be enough storage space to satisfy the AEV(s) requirements.

Robin provides multiple ways to provision an application with AEVs; namely AEV(s) can either be configured within the manifest file of a Robin bundle, within the template of an application to be deployed or can be set at runtime using the Robin UI. Each of these methods are described in the sections below.

5.13.1. Configuring Application Ephemeral Volumes

AEVs can be configured within the manifest file of the bundle the application is based of. More details about configuring AEVs within the manifest file can be found here. In addition they can also be specified at runtime via the input YAML which is used to customize a template an application is based of. More details on how to configure AEVs within a template when creating an application can be found here.

5.13.2. Create Application Ephemeral Volumes from Robin UI

The Robin UI contains full support for provisioning AEVs. When creating an application from a bundle, there is an option of adding one or more AEVs for each role defined in the application manifest. If the required AEVs are already specified within the manifest file, the AEV section automatically appears populated with the preconfigured AEVs. However, these can be modified to suit the needs of the application deployment at. runtime. On the other hand if no AEVs have been specified within the manifest, the APPLICATION EPHEMERAL STORAGE option must be enabled and the respective AEV(s) configured in order for them to be provisioned alongside the application.

Note

A maximum of 10 AEVs per application can be provisioned via the Robin UI.

5.13.3. Application Ephemeral Volumes in Snapshots and Backups

AEVs are not included in application snapshots and backups. They are, however, included in the application spec that is part of the metadata captured with each snapshot and backup. New volumes will be created for each configured AEV when creating a clone of an application from an application snapshot, or a new applications from an application backup.

Note

When creating a clone or new application from a snapshot or backup that contains AEVs, special care needs to be taken if the disk_tag attribute is specified for any of the AEVs. This is because there needs to be an adequate number of disks that not only match the tag specified but also satisfy the storage space requirement for the new AEVs. If this is not the case, the tag specified may need to be modified or removed entirely before deploying the new application instance.

5.14. Auto Disk Rebalance

Robin supports the Auto Disk Rebalance feature. The Auto Disk Rebalance feature manages the storage space automatically of all disks in the cluster after the disk usage reaches a certain watermark threshold. This feature is enabled by default. However, you can disable the Auto Disk Rebalance feature.

Note

By default, the Auto Disk Rebalance feature is enabled on the cluster.

5.14.1. Watermark threshold

The watermark threshold is an attribute that enables you to set the maximum and minimum limits on the disk’s space usage.

There are two types of watermarks:

  • High watermark

  • Low watermark

High watermark - High watermark is the maximum threshold of the disk space that, when exceeded, automatically triggers the disk rebalancing. The default value is 90%.

Low watermark - Low watermark is the minimum threshold of the disk space that, when reached, automatically stops the disk rebalancing. The default value is 80%.

Note

The low watermark value cannot be greater than or equal to the high watermark value.

5.14.2. How does it work

The storage space on a disk is used by one or more volumes. Over time, some disks in the cluster might use storage space to their maximum threshold capacity, while other disks might still have free space.

Robin Central Manager (RCM) continuously collects the physical usage of all disks in the cluster from the Storage Manager (SM) and updates its database. When a disk reaches a high watermark, the disk rebalance job automatically starts to move the volumes from the high watermark disk to the below low watermark disk.

SM selects the volume slices from a high watermark disk and moves these slices to the below low watermark disk. The target disk is chosen based on the following scenarios:

  • The current physical usage of the disk is below the low watermark threshold.

  • The physical usage after the volume slices movement must not exceed the low watermark threshold.

5.14.3. Configure high watermark for disk

You can configure the high watermark threshold percentage value for a disk other than the default value (90%) by updating the high watermark attribute in your cluster.

To configure the high watermark threshold value, run the following command:

# robin config update server disk_used_space_high_watermark <value>

Example

# robin config update server disk_used_space_high_watermark 90
The 'server' attribute 'disk_used_space_high_watermark' has been updated

5.14.4. Configure low watermark for disk

You can configure the low watermark threshold percentage value for a disk other than the default value (80%) by updating the low watermark attribute in your cluster.

To configure the low watermark threshold value, run the following command:

# robin config update server disk_used_space_low_watermark <value>

Example

# robin config update server disk_used_space_low_watermark 80
The 'server' attribute 'disk_used_space_low_watermark' has been updated

5.14.5. View high watermark for disk

You can view the high watermark value for the disk in your cluster.

To view the high watermark value, run the following command:

# robin config list server disk_used_space_high_watermark

Example

# robin config list server disk_used_space_high_watermark
Section | Attribute                      | Value
--------+--------------------------------+-------
server  | disk_used_space_high_watermark | 90

5.14.6. View low watermark value for disk

You can view the low watermark value for the disk in your cluster.

To view the low watermark value, run the following command:

# robin config list server disk_used_space_low_watermark

Example

# robin config list server disk_used_space_low_watermark
Section | Attribute                     | Value
--------+-------------------------------+-------
server  | disk_used_space_low_watermark | 80

5.14.7. Disable Auto Disk Rebalance

As an administrator, you can disable the Auto Disk Rebalance feature when you want to manage the storage space and disks manually. To disable the Auto Disk Rebalance feature, you need to set the value of the high watermark attribute to 100%.

To disable the Auto Disk Rebalance feature, run the following command:

# robin config update server disk_used_space_high_watermark 100
The 'server' attribute 'disk_used_space_high_watermark' has been updated

Note

By default, the Auto Disk Rebalance feature is enabled.

5.15. Handling Disruptions

With Robin, highly available applications can be deployed on Kubernetes as Robin can handle failures of drives, rack or hosts automatically. On a Baremetal setup, volumes can be setup with a replication factor of 2 or 3 to ensure that storage is available even if a drive fails. Users can also choose the fault domain to be ‘host’ to protect against node reboots or lost.

However, in a public cloud environment the cloud disks can be detached from one cloud node and reattached to another one. For example, in AWS an EBS volume can be detached on one EC2 host and reattached to a different EC2 host. Same with GCP where a PD can be moved across GCE nodes. If a cloud node (EC2, GCE, Azure VM) is terminated or rebooted, one would want any cloud drive attached to them (EBS, PD, Block) to be moved to the one or more of the remaining healthy nodes automatically. This is not limited to just cloud disks, but also SAN LUNS that are offered to Robin as disks. The SAN LUNS can also be multi-mounted onto multiple nodes or moved around from node to node. User can still choose to replicate volume on public cloud as it takes sometime to detach and attach drives on cloud platforms.

Just having the storage available during a disruption will not help if Kubernetes can not access it from the Pod. For example a Kubernetes StatefulSet serializes the mounting and unmounting of a volume to protect against possible corruptions. Robin utilizes smart detection techniques to ensure that even if a volume is mounted on multiple nodes, it can differentiate the IOs issued from the previous stale mount and the new mount. With this consistency guarantees, Robin enables the Kubernetes StatefulSet to unmount a volume from a dead node and remount it on a healthy node where the Pod is scheduled to run. Robin actively monitors these events to allow for the fast failover of the Pods without user intervention and consequently enables users to reliably deploy highly available stateful applications on Kubernetes.

5.16. Hardware RAID Controllers

5.16.1. Robin Recommendations

Robin recommends not using Redundant Array of Independent Disks (RAID) configurations for the physical storage devices that you plan to format with Robin storage. To understand the reasons for this recommendation, review the explanations presented here. However if RAID usage cannot be avoided, Robin recommends the following:

  • Use the hardware RAID controllers only to set up RAID-1 protection for boot and OS devices. This ensures that the failure of one device does not take the entire node down.

  • To protect Robin volumes against node and rack failures, you must configure replication across the fault domains. All RAID configurations (RAID-0, RAID-1, RAID-5, and RAID-6) protect data only against device failure on the node. They reduce the storage capacity of the cluster, thus increasing the data storage costs.

  • Robín’s replication provides maximum protection against all hardware failures including storage devices, storage nodes, and rack failures.

  • If a RAID controller has a cache, it must have a battery backup. If the cache on the RAID controller does not have a battery backup, Robin recommends disabling the cache as the data on the cache could be lost during a power outage.

5.16.2. Advantages and Disadvantages

The following are the advantages and disadvantages of RAID usage with Robin:

  • RAID-0 - In RAID-0, data is striped across all devices and provides the best performance. However, if one of the physical devices fails, the data on the RAID volume is lost.

  • RAID-1 - In RAID-1, data is mirrored across two devices. It gives the most redundancy. However, the performance of the volume is determined by the performance of the slowest device in the mirror and the data capacity is reduced by half.

  • RAID-5 - In RAID-5, data is striped across “n-1” devices. The controller calculates and writes parity data to the nth device. The RAID-5 configuration can tolerate one device failure and provides good performance. However, if one of the devices fails, the admin has to replace the device immediately and start a RAID rebuild to maintain the redundancy. All devices should be of the same size or the size of the smallest device decides the total usable capacity.

  • RAID-6 - In RAID-6, data is striped across “n-2” devices. The controller calculates and writes parity to two devices. The RAID-6 configuration can tolerate two device failures and provides good performance. However, the disadvantages are the same as RAID-5.

  • The striped RAID configurations (RAID-0, RAID-5, and RAID-6) provide better IO performance. However, RAID-0 does not give data protection, and RAID-5 and RAID-6 configurations reduce the storage capacity.

  • All RAID configurations are managed outside of Robin CNP. Therefore, the administrator must manually manage the device failures and it leads to an increase in operations cost.

  • If you enable hardware RAID, the RAID controller becomes a single point of failure for all the storage devices on the node. If the RAID controller fails, all data on all the storage devices in the node is lost.

Note

For more details on Robin recommendations for RAID controllers, review the points made here.