Maintenance Mode and HA

[Ashley004]

Hi all

By placing a host into maintenance mode with VM's powered on in a cluster with both HA an DRS enabled , is the host not supposed to automatically vmotion the powered on VM's to another host with resources available ?

Thanks in advance

[jyvesd]

yep but the 'automatic' depends also on the DRS cluster automation level and migration threshold....

[Ashley004]

Migration threshold is set to aggressive and automation level is fully automated.

If I disable HA on the cluster and place a host in maintenance mode the powered on VM's are moved to another host

[jyvesd]

Then DRS will migrate the VMs with VMtion on the other host of the cluster.

FYI Time to time you might experience problem if the VMs has VMotion errors that prevent the migration. Here unfortunately the DRS won't give you the error and will be 'entering maintenance mode' hanging ...So if you need to troubleshoot, you will need to vmotion the remaining VM manually and then the vmotion wizard will give you the error. The best would be to validate the DRS cluster all VMs by vmotioning the vms from-to all hosts.

[ROMCH]

I think I had the same Issue but I cloud solve it. (Environment: 1 VC2.5u2 2 ESX 3.5u2v2 with HA+DRS)

While I tried to set VMware HA Admission Control Option "prevent VMs from being powered on if they voilate availability constaints"

the following VIC Status-Error-Message came up: "Insufficient resources to satisfy configured failover level for HA".

I found that in a certain Resource Group one VM had a fixed CPU Reservation. I changed this to umlimited. Now I could activte without troubles the Option "prevent VMs from being powered on if they voilate availability constaints" and the BEST; the Maintenance Mode works as supposed (VMotion etc)!

Conclusion: I got the impression when you click Maintenance Mode on a ESX and the HA Option stays on "Allow VMs to be powered even if they voilate availability constaints" and your Resource Conraints are voilated then VMotion does not start automaticly.