We had an issue earlier this month where we could not backup anything using 3PAR storage snapshots. We have all of our 3PAR volumes presented to our physical Windows 2012 R2 proxy server and we were successfully backing up our environment with storage snapshots for about a year. After upgrading to v9, everything worked fine for a few days but then backups began to fail. Veeam would initiate the storage snapshot on the 3par, but the storage snapshot was never presented to Windows so the backup couldn't begin. We attempted to launch Device Manager but it would hang and never open. We also noticed that the boot time for this windows proxy server takes an abnormally long time to boot up. Using process monitor, we saw that the proxy was constantly adding regkeys for 3PAR volumes. The regkey for MPIO and the 3PAR volumes was 350 MB. Based on all of this, it seems that when the proxy attempted to get data from the storage snapshot, windows could not see it because it was taking too long to present the snapshot.
We uninstalled MPIO and deleted the regkeys. After a reboot, the system started up in a normal time and device manager launched without an issue. We reinstalled MPIO and tested some backups successfully. It appears that every time Veeam takes a storage snapshot for a backup, it presents that snapshot to the proxy and adds it as a device. Over time the number of devices seemed to have added up and caused system performance issues.
Everything is currently working fine, however, over the last few weeks, the regkey for MPIO has continued to grow to an unusually large size and I'm afraid that the same issue will occur again.
I have a support case open, #01688144, but have not made much progress. Has anyone else experienced an issue like this?