Does anyone know if they made any changes to how DSU’s are utilized in 6.5.1 ?

We recently upgraded to NBU 6.5.1.  That is the only difference in our backup environment.  The hardware, network settings, policies and schedules are all exactly the same as our 6.0 MP4 setup.  Everything was imported via full catalog restore.  We send all of our backups to 2 Data Domain disk storage devices which then replicate to our DR site.

Since the 6.5.1 upgrade, huge swathes of our backups have been sitting queued until their backup window closes before returning a 196.  We don't really want to start playing around with the schedules as they were working just fine prior to the upgrade.  We are looking into the Open Storage option (OST) but this is more from the point of view of adding additional functionality rather than bringing 6.5.1 up to par with 6.0 when using disk storage !!


Does anyone have any ideas on what might have changed regarding policy execution, job scheduling or NBU’s handling of disk Storage that could be causing this new and very annoying issue ? 

Thanks

Mark