We've been using BackupPC (http://backuppc.sourceforge.net/ http://backuppc.sourceforge.net/) to accomplish something similar for a long time, and have been ama

We've been using BackupPC (http://backuppc.sourceforge.net/ http://backuppc.sourceforge.net/) to accomplish something similar for a long time, and have been amazed at how it's able to store huge amounts of backups on relatively small amounts of disk space. It's highly configurable and has a decent web interface. Sometimes, though, it can be challenging to get it working, and it has a few other issues (e.g., moving backups for systems from one pool to another) that can make it difficult in the long-run for some use-cases.