Backups and Snapshots

Local Files

Files stored on the local hard drives of CS Department machines are not backed up.  That includes files in /tmp, /ltmp and /var/tmp, and all system software and directories.

CS Network Filesystem

The CS department's shared filesystems are hosted on OIT's file service.  All files served from there are backed up using snapshots.  When a file is changed or deleted on these filesystems, the previous version of the file is saved in a snapshot.  The schedule for snapshot retention is:

After 6 months, deleted files and older versions of changed files cannot be recovered.  There are no provisions for long-term filesystem backups.


Snapshots are point-in-time, read-only copies of a filesystem that exist in parallel with it.  Snapshots are provided by the filesystem itself, and are accessible, in our case, from a hidden subdirectory, .snapshot, which is present in every directory on the filesystem.  By navigating into this subdirectory, you can view or restore your files from various points in the past.

How you use the snapshots depends on whether you're using Windows or Unix.

Disaster Recovery

All CS network filesystems are continuously replicated to an off-site location with the exception of the /nbu ("not backed up") file hierarchy.