Of the new features coming in the R2 versions of Windows Server 2008 and SCVMM, I think these two are the obvious winners:
Support for Live Migration: With Windows 2008 R2 adding support for Live migration, it’s now added as a new migration option in VMM R2. Live migration requires the source and destination host to be part of a failover cluster and that the VM is on a shared storage. Live migration means that there is no user perceived downtime; since the VM’s memory pages are being transferred, the hosts’ processors need to be the same (manufacturer and processor architecture). Our competition claims that Vmotion doesn’t require clustering but this only works for planned downtime and not for unplanned downtime. By combining Live migration and clustering, Hyper-V addresses both planned and unplanned downtime.
Multiple VMs per LUN: VMM 2008 didn’t allow placing multiple VMs per LUN even though Hyper-V allowed it and the reason was that the LUN ownership was on a per host basis. This meant that migrating any VM on that shared LUN would result in all other VMs being migrated as well which can result in a confusing user experience (I’ve blogged about this at length). With CSV (Clustered Shared Volumes) in Windows 2008 R2, a single LUN is accessible by all hosts within a cluster. This enables a VM that’s on a shared LUN to be migrated without affecting other VMs on that LUN. As a result, with VMM R2, we’ll allow multiple VMs to be placed on the same LUN if CSV is enabled on the cluster.
That is from the beta release announcement for SCVMM. I have downloaded the beta, but haven’t had time lately to get it setup. I am hoping to work on that this coming week…