68018: Acronis Cyber Infrastructure: Alert 'iSCSI LUN <lun_id> of target group “<target_group>” is set to failure domain “disk” even though <number_of_nodes> nodes are available.'

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Last update: 20-12-2022

Symptoms

The following alert is being observed in MONITORING > ALERTS on Acronis Cyber Infrastructure cluster with block storage configured:

iSCSI LUN <lun_id> of target group “<target_group>” is set to failure domain “disk” even though <number_of_nodes> nodes are available. It is recommended to set the failure domain to “host” so that the LUN can survive host failures in addition to disk failures.

e.g.:

Cause

The alert is intended to warn about non-optimal storage policy configuration of iSCSI LUN (volume) - in case of multi-node cluster is it highly recommended to have Failure Domain of LUN configured as 'host' rather than 'disk' for better reliability. Initially storage policy parameters are being selected during volume creation.

Solution

Use CLI to verify and change volume (LUN) storage policy parameters:

1. Obtain Volume ID value via WebCP > Storage services > Block storage > Volumes > click on issued LUN

2. Get attributes of the volume specifying obtained Volume ID, e.g.:

[root@node01 ~]# vstorage-target vol-attr get -id 4b6b3012-d465-4a56-b264-bb7be39eb2c3
{
  "chunk-size": "268435456",
  "client-ssd-cache": "1",
  "encoding": "3+1/1",
  "failure-domain": "disk",  
  "failure-domain.int": "0",
  "immediate-write": "1",
  "strip-width": "1048576",
  "stripe-depth": "3",
  "tier": "0"
}

3. Change the failure-domain attribute to 'host':

[root@node01 ~]# vstorage-target vol-attr set -id 4b6b3012-d465-4a56-b264-bb7be39eb2c3 -vstorage-attr "failure-domain=host"

4. Verify that attributes of the volume are changed:

[root@node01 ~]# vstorage-target vol-attr get -id 4b6b3012-d465-4a56-b264-bb7be39eb2c3
{
  "chunk-size": "268435456",
  "client-ssd-cache": "1",
  "encoding": "3+1/1",
  "failure-domain": "host",  
  "failure-domain.int": "1",
  "immediate-write": "1",
  "strip-width": "1048576",
  "stripe-depth": "3",
  "tier": "0"
}

Chunk replicas of the issued volume will start rebalancing accordingly, the alert is expected to be cleared out automatically in a while.

More information

See more details in documentation:

ACI Administator Guide: Provisioning block storage space

ACI Administrator Guide: Storage Policies

ACI Administrator Command Line Guide: Accessing Storage Clusters via iSCSI

ACI Administrator Command Line Guide: Managing iSCSI Volumes

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