DRS does not automatically migrate VMs to an empty and compatible ESXi host.
Article ID: 400431
Updated On:
Products
Issue/Introduction
In some situations, DRS may not migrate VMs in a cluster to an empty host, even though it shows all signs of it being compatible.
There are no issues with moving VMs manually to the host.
Environment
vCenter Server 6.x
vCenter Server 7.x
vCenter Server 8.x
vCenter Server 9.x
Cause
DRS will not migrate VMs if the benefit outweighs the cost of the migration. Therefore, a cluster full of VMs with excellent DRS scores (90% +) will usually not create recommendations to move any VMs to an empty host. This can be perceived as an imbalance in the cluster.
You can confirm the DRS scores for VMs in the UI by clicking on the Cluster Object > Monitor > vSphere DRS > VM DRS Score.
Resolution
No action is needed.
The VMs will be moved when enough contention is created in the cluster to merit a DRS recommended vMotion. Additionally, newly powered on VMs will likely come up on the empty host.
Additional Information
If another host in the cluster is put into maintenance mode and VMs are not migrated to the empty host, there may be an issue with compatibility of the host. Check the vCenter /var/log/vmware/vpxd/vpxd.log with the logging level set to verbose for more information.
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