bonezau1
Contributor
Contributor

Horizon linked clones & vSAN disk rebalance

I'm running VMware Horizon 7.4 with a linked clone pool for our users virtual desktops. It's running on a vSAN (version info at bottom of post).

When our users log off their VDI session, the VM is destroyed and re-composed from the parent replica.

Every day we are seeing vSAN disk re-balance required and the cluster has a yellow exclamation mark, this is obviously due to the VMs being constantly deleted and re-created. Sometimes the the vSAN re-balance required alert goes away but it seems to be there about 4-5 days a week.

If we initiate a disk re-balance on the cluster it completes successfully but then usually the next day it's again complaining it wants to re-balance.

Is there anything we can do to get rid of this constant alerting or should it just be ignored?

vSAN 6.2 Patch 6 with On Disk version 3

ESXi 6.0.0 build-6921384

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TheBobkin
VMware Employee
VMware Employee

Hello bonezau1

"Sometimes the the vSAN re-balance required alert goes away but it seems to be there about 4-5 days a week."

This is triggered if there is more than 30% usage disparity between lowest and highest use capacity-drives (across the entire cluster).

If you have relatively smaller capacity-tier drives and/or a lot of data-churn then this is more likely to be occurring.

In your case there is no point using Proactive Rebalance as this would just be extra data-moves, you are re-filling the emptier disks in a matter of hours/days anyway.

You can safely ignore this particular health alert as it is informational in nature only and your use-case explains why it is present.

vSAN 6.6 introduced the capability to silence particular Health checks:

How to silence VMware vSAN Health Checks | Virten.net

Bob

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