VM Guest cluster OS in Hyper V 2012 Server

Hi to all.

I'm heavy testing VM Guest Clustering in Hyper V server 2012 Host clustered Environment.

I install a Windows 2008 R2 Sp1 Guest Cluster on two Virtual Machines using Virtual FC HBA. Everything Works fine, the cluster works fine with the vm sparse on the two hyper V host or on the same, live migration too.

First Question: Is the Windows 2008 R2 sp1 OS supported by Microsoft in a guest cluster environment, or the only supported OS is Windows 2012?

Second Question: During live migration of a clustered VM someone experienced EventID 57 Source NTFS during heavy IO on a clustered Disk ?

Thanks in advance.

vannig