Slow copy speeds when using Persistent shadow copies

May 15, 2013 at 7:24 PM
I'm having a strange issue when testing AlphaVSS for use in my project. I'm also using AlphaFS, but I believe the problem relates more to VSS.

I'm creating a shadow copy of my C drive, no problem there, and I can copy the Windows folder to another drive in about 20 mins when accessing it directly via the copy.

The problem is I need to make the files available to another application, so I'm using a persistent snapshot and ExposeSnapshot to make it available via a drive letter. When I do this the same copy process takes several hours (it's about 30GB). Even if I access it via the snapshot exactly as I was doing before and not the drive lettter it still takes hours, so it appears to be related to either making the snapshot persistent or exposing it.

I'm using AlphaFS to test the copy currently, has anyone else had this problem? 20 mins to copy 30GB is ok, several hours just isn't realistic.
May 16, 2013 at 12:23 AM
Edited May 16, 2013 at 12:24 AM
It appears this problem is cause by the SymSnapService (part of Norton Ghost and other Symantec backup/Imaging utilities). As soon as the snapshot is exposed it decides it wants to access the snapshot and locks it until it's finished!

Is there any way to set which applications/services have access to the snapshot or set a priority? It appears SymSnapService has priority over my application, so there must be something that gives it that priority. Maybe a service has priority over an application?