HA without DRS ?

[VgeekFreak]

How would the VM placement be done without DRS.

I presume, in a cluster that has HA enabled , VMs would be powered on randomly on other available host ?

I've browsed through available posts on blogs, I find them ambiguous ..

[MKguy]

It would simply power on the VM on the host it currently registered on.  So if you create a new VM, you will have to choose the inital host and the VM would always be started on this one, unless you vMotion it off or register it on another host. (It could also be that you will be asked like in manual DRS mode, but I don't think so.)

Your question seems a bit ambiguous.

Or were you talking about how HA restarts will be initiated? DRS only relevant to this if you have DRS MUST affinity rules. Otherwise, DRS is completely ignored. But DRS could of course kick in later to correct imbalances caused by the restarts.

See http://www.yellow-bricks.com/2010/06/16/which-host-is-selected-for-an-ha-initiated-restart/

[weinstein5]

HA will restart the VM on the hosts that have the available resources to support the VM - HA will continue until the resources are exhausted -

[VgeekFreak]

My apologies !

What I exaclty meant to ask is...If a host failes in a ONLY-HA cluster...how would the VMs be placed ...how and who makes the decision when DRS is not configured in such a case. Thanks

[karthickvm · Accepted solution]

Hello vGeek,

If you have HA Cluster (only HA Not DRS enabled), when one host fails the VMS will be restarted on available hosts based on the Adminission control policy and restart priority.

The HA agent installed on the Host will take of restarting the VMS.

I would like you to have a look at the below Articles for detailed explanation.

http://www.yellow-bricks.com/vmware-high-availability-deepdiv/

http://blogs.vmware.com/vsphere/2012/06/vsphere-ha-admission-control-calculation-for-memory.html

Hope this helps.

[VgeekFreak]

Thanks Karthick ! that helps ..