Hello.  PowerPath Migration Enabler (PPME) is a non-cluster application that under limited conditions can be used to migrate in clusters. It is not aware of the persistent reservation commands.  PPME does not transfer the registration from source to target during the "commit" process. Once a migration is committed and the cluster starts using the target/new device, it expects to find a persistent reservation registration on that device.  However, it does not have the expected registration. For that reason we need to off-line the resource group, commit the migration, then restart the groups.  This will initialize the new disk with the appropriate registration on the new device.  This doesn't apply to Windows 2003 because it doesn't use the SCSI-3 persistent reservation that Windows 2008 uses.  There will be enhancements to PPME in a coming version that will not require this step.  I hope this helps.
I have been using PowerPath Migration Enabler Host Copy to perform migrations from a CX3-20 to a CX4-120.  It has worked great on my windows servers enabling me to do host-based migrations with zero downtime.  Now it comes to migrating the Windows 2008 clusters.  I'm reading through the PowerPath Migration Enabler 5.5 User Guide and on pages 51-52 it discusses using PPME for clusters.  The steps seem the same until it comes to step 8.  It says:  On Windows 2003 clusters when ready to commit the migration run "powermig commit" and you are finished.  On Windows 2008 clusters it says to first "bring the failover groups offline, stopping the applications", then run "powermig commit", and finally bring the failover groups back online.  Am I reading this correctly that I must bring the groups down in order to commit the migration, but I did not have to do so on 2003?  If so, that is disappointing, because PPME has been great for all of my other migrations.  I wonder why the groups have to be shut down in 2008 when they did not need to be in 2003.
Question about PowerPath Migration Enabler for Windows 2008 Clusters