Comments on: Isolation mode on VMware ESX servers

By: Paul

Paul — Thu, 31 Dec 2009 21:32:34 +0000

Good news, probably. VMWare KB article 1003165 dated 8-Dec-09 says “For VMware VirtualCenter 2.5.x and later, the default isolation response is Leave VM Powered ON.”

By: Biju

Biju — Thu, 05 Mar 2009 11:26:40 +0000

Yes, Theo is right. In Isolation mode the ESX server will shut down all the VM’s to prevent split brain scenario. That is One ESX Host won’t know what the Other ESX host in the cluster is doing with its VM.

Hence it shuts down VM (not gracefully though). This will ensure that the VM files are unlocked from the VMFS and can be started from other ESX server.

By: Rickard

Rickard — Thu, 26 Feb 2009 21:17:57 +0000

You have a point there. The scenario would be similar to when a host has failed.

David: Hohoho :)

By: Theo

Theo — Thu, 26 Feb 2009 20:10:58 +0000

The single isolated vmware host has no way to tell if the same thing happened to the other servers so it seems very logical.

The only thing the vmware host can safely assume is that the other vmware hosts in the cluster will mark the hosts as failed and start the guests that were running on the failed vmware host.

By: David

David — Thu, 26 Feb 2009 11:55:48 +0000

“I’m still not sure why the default is to shut down the machines. I mean, won’t forcibly shutting down a virtual machine potentially cause more problems than letting it run without a network connection?”

Oh yes. Definitely. No doubt at all in my mind.

/David