High Disk Latency on vSAN cluster may impact VM performance.
Article ID: 393495
Updated On:
Products
Issue/Introduction
Symptoms:
Virtual Machines running on the vSAN cluster may stay hung or not responding when launching VM console.
When checking for the vSAN cluster performance, you may see cluster level latency reported for READ and WRITE.
Environment
VMware vSAN 7.x
VMware vSAN 8.x
Cause
The issue is seen when there is a disk latency on one or more drives used for vSAN.
When checking for performance stats under vSAN cluster > Support > Performance for diagnostics for individual disks stats, you may see latency reported for disks under LSOM.
Resolution
To address to the issue immediately, after identifying the problematic host, place the host into maintenance mode using ensure accessibility or full data migration and monitor the performance on the vSAN cluster.
If the performance improves, please work with hardware vendor to get the hardware issues resolved.
The following article can be used for instructions on Requirements when replacing disks in a vSAN cluster
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