CSL: Unix Backups

CSL: Unix Backups

The CSL performs a combination of full and incremental data backups to help ensure the availability and integrity of programs, documents, and other data of importance to the C.S. community.

Backups defined:

Backups are the copying of data from primary (disk) storage media to secondary (disk and tape) storage media for the purposes of data preservation, data restoration, and disaster recovery. Both the process and the recorded tape media are referred to as backups.

Additionally, newer hardware allows some filesystems to provide multiple, daily backups called snapshots. Please see the Snapshots page for more information on this option.

What gets backed up:

Most data partitions (home, project, mail, etc.) on departmental Unix servers are backed up. Exceptions, such as /usr/project/xtmp/, are clearly noted. In most cases, partitions such as root, /var/, and /tmp/ are not backed up.

Departmental Unix desktop machines are not backed up, except for these directories: /var/spool/calendar, /var/spool/cron.

Departmental PC's and Macintosh computers are backed up separately, and by request only. Please see the PC Backup page for more information.

Some projects, such as ARI, have their own equipment, personnel, and backups.


The CSL performs a mix of full and incremental backups on a regular schedule. Full backups are performed near the beginning of each month primarily using disk staging and LTO and AIT tapes. Incremental backups are performed daily using disk staging and LTO tapes.

Some project disks or unusual systems are backed up less frequently. If you have any questions about the backup policy concerning a particular partition, disk, or computer, please contact the Lab Staff.


Full backups from January and July are kept indefinitely (due to limited shelf-life of recordable media, this probably means five to ten years). (Some older backups have been copied to newer media, so please feel free to inquire if you need something that may be archived.) Full backups from other months are kept for two years, after which the tapes are reused or erased.

Incremental backups are retained for at least one month, and the tapes are eventually reused (ie, overwritten).

Off­site copies:

Copies of monthly full backups, going back at least one year, are kept off-site.


Departmental backups are performed using a system of in-house-written shell scripts. These scripts utilize the standard Unix dump and restore mechanism for the low-level aspects of the backup system. On Solaris, see the man pages for ufsdump(1M) and ufsrestore(1M) for more details. On Linux, see the man pages for dump and restore. The NetApp Filers use a dump and restore very similar to those on Solaris.


If you have data that you would like to permanently archive, it is possible, with Lab Staff assistance, to make tape, CD, or DVD archives. CD and DVD are probably the longer-lasting and more convenient (for later access) of these options. The Lab Staff are available to discuss various media and their capacities.


If you need one or more files restored from tape backups, please fill out the Restore Request Form. You might want to check for online Snapshots first.

Alternately, you can contact the Lab Staff.