VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
Appendix D - Advanced Settings
There are only two advanced settings that can be considered tunable at this point in
time.
Caution: While VMware recommends against changing any of these advanced settings,
you need to ensure that all hosts in the cluster have the same settings if you modify any
of the advanced settings for Virtual SAN.
VSAN.ClomRepairDelay
The vsan.clomrepairdelay setting specifies the amount of time Virtual SAN waits
before rebuilding a disk object. By default, the repair delay value is set to
60 minutes; this means that in the event of a failure that renders components
ABSENT, Virtual SAN waits 60 minutes before rebuilding any disk objects. This is
because Virtual SAN is not certain if the failure is transient or permanent.
Changing this setting requires a clomd restart.
Note: If a failure in a physical hardware component is detected, such as an Solid
State Disk (SSD) or Magnetic Disk (MD), this results in components being marked as
DEGRADED and Virtual SAN immediately responds by rebuilding the impacted
components. KB article 2075456 has instructions on how to change this setting.
VSAN.ClomMaxComponentsSizeGB
By default VSAN.ClomMaxComponentSizeGB is set to 255GB. When Virtual SAN
stores virtual machine objects, it creates components whose default size does not
exceed 255 GB. If you use physical disks that are smaller than 255GB, then you
might see errors similar to the following when you try to deploy a virtual machine:
There is no more space for virtual disk XX. You might be able to continue this session by
freeing disk space on the relevant volume and clicking retry.
In situations like this, you may need to modify VSAN.ClomMaxComponentSizeGB to
s size that is approximately 80% of the physical disk size. KB article 2080503 has
instructions on how to change this setting.
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