Live Rollback of 20+TB Volume Does Not Allow Access While Rollback is Running
When attempting to restore a 23tb data Volume from a protected 2008 agent to a diff 2012 agent with 32tb Volume, the live rollback starts but you cannot access the volume and an "INVALID PARAMETER" error is reported.
The core will start the live rollback and it appears to be working but when you attempt to access the target volume you get "Access Denied" Errors and cannot get to the data being restored as you would expect being a live rollback
The source recovery point being used is from a 23tb volume on a 2008 R2 agent. The protected disk on the agent when created was formatted as NTFS with 8K "byte per cluster"
The target 32tb volume on the 2012 agent was formatted as NTFS with 16K "byte per cluster" which is required for a volume of that size on server 2012
The target volume must be formatted using the same values as the source disk in order for the live rollback to allow access to the data while the restore is being processed.
Anything formatted above 16TB has 8K or 16K "byte per cluster”
Bytes per sector on a formatted NTFS volume:
<16TB = 4K
>=16TB = 8K
>=32TB = 16K
Source volume is 8K and restoring to a 16K bytes per cluster target volume when sized above 32TB
This causes the data to potentially be inaccessible during the live rollback
If you were to Restore to a target volume that was formatted with the same bytes per cluster, the restores are successful because the "bytes per sector" match with the source volume / recovery point