Colleague is also backup up to tape on a nightly basis using the cisbackup script.  The script is configured to take a zfs snapshot of the Colleague file systems every morning at 1 AM, and then copy that snapshot to a tar file on the tape drive attached to the Colleague server.  Tapes are changed daily, Monday to Friday, and each Monday-Thursday tape is reused every week.  The Friday tape is marked as a weekly tape and kept in a fireproof safe for one year.