All ESXi versions

18 May: VMs don’t show in VirtuCache GUI due to intermittent Datastore connectivity

VirtuCache performs disk heartbeats periodically. If there are Datastore connectivity issues in VMware, these disk heartbeats may fail intermittently, in which case VirtuCache treats the Datastore as unreachable and VMs that are in the Datastore don’t show in the VirtuCache GUI. VirtuCache takes this precautionary measure to prevent the Administrator from changing…

27 Mar: SSD failure alert in vCenter

If a SSD starts to fail, it first starts to slow down , especially for writes, then it becomes read only , and at that point VirtuCache is not able to write to the SSD so VMs and Datastores move to uncached mode automatically. Your VMs go back to performing as…

25 Mar: In case the Write-Replication network fails

If the write-replication network fails, then VirtuCache keeps trying to replicate writes for 30seconds, during which time writes are not being acknowledged. After the 30 second period, VirtuCache times out the writes. Then VirtuCache freezes IO till the write cache is synced with backend SAN. Since we keep upto 2…

13 Mar: VMs not in Write-Back mode because of Replication Network issues

Caching policy of ‘Write-Back 1 Replica’ is assigned to VMs or Datastores, but the operational state remains ‘Write-Through’. The reasons could be one or more listed below. The VirtuCache replication network is the vmotion network and the vmotion network might be using the vmotion stack that precludes all other traffic from…

07 Mar: VirtuCache compatibility with VMware snapshots

This article applies to snapshots in VMware (not for storage appliance snapshots) that are used for various purposes including for backups by Veeam, Commvault and other backup software. VirtuCache triggers accelerated destaging when a snapshot is created and ensures that the base snapshot is not readable by other hosts until…