I manage a few Windows 2012 servers, which, between them all, host millions of small files. I have DFS namespaces set up and tried to get DFS replication working as well. DFS replication didn't seem to pan out (will probably try to get it running at some point in the future though), so for now I've removed all replication groups and started using robocopy + task scheduler to synchronize files as a temporary solution.
On two of my servers, the DFS Replication service is still running in the background, but it's OK because they're not consuming very many resources. However on one of my servers, the DFS replication service is constantly using around 1.5 to 2 GB of RAM and 1 to 2% CPU.
I know my server's network shares are being used heavily, but if I'm not even using DFS replication at all, why is the replication service consuming so much RAM? Is it still trying to keep track of files even though none of them are being replicated?
How large is the database? This is normal behaviour of ESE. When the OS needs the ram for something else ESE will release it.
Please see hardware tuning section of http://blogs.technet.com/b/askds/archive/2010/03/31/tuning-replication-performance-in-dfsr-especially-on-win2008-r2.aspx