This week, Microsoft is announcing that Windows 2008 R2 will add a new feature to Failover Clusters called “Cluster Shared Volumes (CSV)”. This feature is being introduced so that they can support the Live Migration feature for Hyper-V. You can get more details about CSV and other 2008 R2 features in the following document:
Windows Server 2008 R2 (Beta) Reviewers Guide - http://download.microsoft.com/download/F/2/1/F2146213-4AC0-4C50-B69A-12428FF0B077/Windows_Server_2008_R2_Reviewers_Guide_(BETA).doc
They are giving sessions about this at WINHEC and TechEd EMEA this week. Unfortunately, I won’t be attending these, but it’ll be really interesting to see where this goes in the future. This certainly gives you an idea of where Microsoft might be heading for future releases of Windows. It seems to me that they’ll be heading towards a “shared everything” model in the future, stacking NLB and perhaps Compute cluster all in one massive cluster solution.
In talking with the cluster team, they don’t currently plan to support this feature in a multi-site cluster environment…it’s not yet clear why. Perhaps it has something to do with possible network latency between the nodes. I'll post more about this as I get the details.