VSAN flash disk failed and unable to perform backups or snapshots of VM's

Products

• VMware vSAN

Issue/Introduction

Following the flash disk failure on a single node of a 3 node cluster the following error is present  when a snapshot of a VM is attempted. 

There are currently 0 usable disks for the operation. This operation requires 1 more usable disks.  

Environment

VMware vSAN (all versions)

Cause

An insufficient number of Disks are currently present in the environment for component placement After disk fault. 

Example

3 host cluster 1 disk-group on each host. 

Ftt1 storage policy. 

Cache disk failure on host 1 you will no longer be able to place any new objects.  

Example

4 host cluster 1 disk-group on each host. 

Raid-5 storage policy. 

Cache disk failure on host 1 you will no longer be able to place any new objects.  

 

Resolution

FIX

Replace a Flash Caching Device on a Host in vSAN Cluster 

Workaround

The below workaround is only a temporary fix and the advanced setting /VSAN/ClomForceProvisionPlacements should not be left permanently enabled as your Data won't be properly protected for redundancy which could lead to data unavailability or even data loss.

For vSAN 6.7 onwards the following workaround is available: 

You can set the advanced config option on all Hosts to be able to create/revert snapshots until the Fault Domain issue has been resolved:
esxcfg-advcfg -s 1 /VSAN/ClomForceProvisionPlacements

Once the Fault Domain issue has been resolved, revert the setting back on all Hosts by:
esxcfg-advcfg -s 0 /VSAN/ClomForceProvisionPlacements

 

Refrence kb

 

vSAN -- Creating/Reverting Snapshots fails -- Fault Domain Error