I ran a simple analysis comparing the zip results versus dedup. I am using 2008 R2 but evaluating the dedup savings using the tool ddpeval.
For my test, I only backed up a single host running two guests. Each guest is a virtual domain controller running 2008 R2. They use about 25GB of storage on the host machine.
HVBackup generated two zip files about 10GB in size. That is a great reduction! Running ddpeval against these shows deduplication under 2012 would not help much which is expected since the files are compressed.
Evaluated folder size: 19.39 GB
Files in evaluated folder: 3
Processed files: 3
Processed files size: 19.39 GB
Optimized files size: 18.49 GB
Space savings: 119.80 KB
Space savings percent: 0
Optimized files size (no compression): 18.49 GB
Space savings (no compression): 119.80 KB
Space savings percent (no compression): 0
I unzipped the files into a separate directory tree and ran ddpeval on those directories. The results are pretty good:
Evaluated folder size: 53.66 GB
Files in evaluated folder: 8
Processed files: 6
Processed files size: 53.66 GB
Optimized files size: 13.31 GB
Space savings: 40.35 GB
Space savings percent: 75
Optimized files size (no compression): 31.86 GB
Space savings (no compression): 21.80 GB
Space savings percent (no compression): 40
The space savings would be much higher as the VM density increases if the guests are all running the same Windows OS. Most of our VM hosts are running 10-25 guests, all using 2008 R2. I put this here only to suggest that the ability to turn off
zip compression could be valuable with the new release of 2012 and using that as a storage point for the backups. I suspect the overall timeline of backups and deduplication would be faster than the zip compression currently used (just a guess).