We have an existing 3 node cluster running 2008R2 Hyper-V. Back end storage is an EqualLogic iSCSI SAN. We are replacing the host servers in this cluster and are looking at upgrading to server 2012 at the same time. Is there any way to do this without downtime? Maybe add a 2012 server to the 2008R2 cluster and migrate virtual machines? From what I've read I'll have to plan an outage to move the virtual machines between the 2008R2 cluster and a new 2012 cluster. Is this right? No zero downtime upgrade path?
I found the correct answer and the short version is there is no zero downtime solution to migrate from a 2008R2 Hyper-v stack to a 2012 stack. Longer version is here: http://blogs.msdn.com/b/clustering/archive/2012/06/25/10323434.aspx