The School of Computing currently provides backups using a disk-to-disk system for the three filesystems on our main file server: home, res, and sys. Backups are currently done at least daily and as often as every hour depending on the load it puts on our file server. Retention times are also under investigation and will depend on how much data changes over time. We are hoping to be able to keep at least six months' worth of monthly backups. The main file server already provides snapshots in finer granularity for the current month.
A full description of the snapshot service and more details on the filers can be found in our Netapp FAQ.