VMware vSphere Virtual Machine Live Clones Across Datacenters

Posted on 17 Feb 2010 by Ray Heffer

vMotionPrior to VMware ESX 4 (vSphere) it was not possible to clone a running virtual machine to another datacenter, or to a virtual machine data store that wasn’t available on the source host. Now with VMware vSphere it is possible to clone a running virtual machine to another datacenter, even if the destination data store is not presented to the source host.

How does this work when the target hosts volume isn’t even accessible on the originating server? The answer is in the Service Console network. When source and destination disk volumes are present, then it will initiate a disk to disk transfer (over iSCSI or fibre channel). However, when the target storage is unavailable it will now use the Service Console network to transfer the data. Magic!

This is an excellent feature, as prior to ESX 4 I had to temporarily present the target volume to the source host during the migration or cloning process. Now I can keep storage between my datacenters seperate.

Why the Service Console Network? Providing the service console network is used for management only, this is the best option. You certainly wouldn’t want the VMkernal network to be saturated with traffic generated from a storage migration, as this would impact VMotion.

Thanks again to VMware for another excellent feature!