VMs are not migrating automatcally after patch updation on the Host

[raghavendrats]

I have a vsphere 4 cluster with 3 ESX 4 Hosts in that. When I updated patches on one of these Host's through Update manager It migrated all the running Vms in the Hosts to other 2 Hosts in the cluster without any user intervention and entered to maintanace mode to apply the patches. (As we have enabled HA & DRS in the cluster)

But the question is the Host is not automatically migrating back VMs which were running on this Host after reboot. I need to do migrations manually now. Is there any particular ettings in HA or DRS to make this happen automatically?

Appreciate any replies..

Thanks.

[sflanders]

Why do you need to migrate them back? Depending on your environmental requirements and how you have configured DRS and HA this could be expected / normal behavior. The VMs will only be migrated if:

• The VMs require more resources than the ESX host has available (unless you disable DRS for particular VMs)

• To load balance VMs as defined by how conservative or aggressive you have DRS configured

• To keep or separate VMs based on DRS rules you have configured

If you have the default DRS and HA configuration and your VMs do not consume most of the resources on the two ESX hosts they now occupy then the may not move as it is deemed unnecessary. It should be noted, that if any of the above bullets apply that they may not kick in right away as vCenter Server may take a couple minutes to determine an imbalance and correct it.

If you are asking can the VMs always reside on the same ESX host even after a remediation, then the simple answer would be not easily.