DeDuplication is one of the coolest new features on Server 2012 and I can’t wait to get the new R2 with all improvements.
All (File) Servers I’m using are brand new setups but there is an older system which was 2008 R2 and upgraded inplace a couple of months before without worries.
There are many image files, drivers, backups laying around but the dedup rate was very low right from the beginning.
Usually I can see dedup rates around 40 – 50% on most fileservers. Sometimes much more especially If there are sys preps and Microsoft related stuff.
This one special fileserver was running out of space the second time and it seems there is a problem with the garbage collection.
I started a thread at the Technet Forum and got a couple of informations.
The interims solution for me at the moment is a powershell command to run the clean up manually and get space back.
PS C:\> Start-DedupJob E: –Type GarbageCollection -full
Within the next days I’m crawling a bit deeper and take a look into the system log trying to get more useful error messages or something.