vSAN OSA clusters running on 8.0 U2 or 8.0U2b may hit a rare condition where the vSAN datastore reaches out of logical space due to frequent deletion of VMs.

Products

• VMware vSAN

Issue/Introduction

This KB provides a workaround to the “Out Of Logical Space” condition for vSAN OSA clusters running vSphere 8.0U2 and 8.0U2b

Symptoms:

• VMs fail to deploy/create with the error "There is no more space", yet there is plenty of space on the vSAN datastore.
• vSAN Health "physdiskcapacity" reports out of logical space
• Examples of errors seen in the Logs, not specific to any Host(s):

2024-03-06T20:41:02.679Z Wa(180) vmkwarning: cpu64:2561511 opID=ac4b68ff)WARNING: 

2024-03-06T22:57:53.736Z Wa(180) vmkwarning: cpu124:2099922)WARNING: LSOM: LSOMOutOfLogical:12361: Throttled: cp 4194304 cu 0

2024-03-06T23:07:05.161Z Wa(180) vmkwarning: cpu71:2099290)WARNING: VSAN: VsanSparseWriteDone:4590: Throttled: Write error on '3a1d9e51-eba6e865-06d4-c916-727e-00620bc23b50': token status 'No space left on device',SCSI status 8 (OK:BUSY)

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Environment

VMware vSAN 8.0.x

Cause

When a large number of VMs are deleted and space is not reclaimed fast enough while new VMs are being provisioned  (VDI like workloads) we might encounter this out of logical space scenario.

Resolution

This is a known issue affects ONLY vSAN OSA 8.0 U2 and vSAN OSA 8.0 U2b under very specific conditions explained above.

VMware recommends applying the configuration changes suggested in the "Workaround" section to mitigate the risk of encountering this issue proactively on vSAN OSA 8.0 U2 / vSAN OSA 8.0 U2b releases.

VMware is planning to address this issue in a future release.

Workaround:
Apply the below advanced configuration on all hosts in the cluster and run auto-backup.sh:

esxcfg-advcfg -s 0 /LSOM/lsomPlogZeropV2;/sbin/auto-backup.sh