A: Several IT pros have reported problems with Hyper-V clusters after installing Windows Server 2008 R2 SP1. Reports infer that updated clusters of three or more nodes begin displaying storage test failures while running the cluster validation wizard.

One example error message resembles the following:

Disk with identifier [ID] has a Persistent Reservation on it. The disk might be part of some other cluster. Removing the disk from validation set.

There's no published fix for the errors as of this writing. However, the problem is being discussed at the Microsoft community site. Until a resolution is found, Microsoft is urging caution in installing SP1 to Hyper-V cluster nodes.