Backups, Restores, and Snapshots

Since August 2010 we have been outsourcing our backups to Brown University Center for Computation and Visualization (CCV). An incremental backup is done nightly (ummm, sometimes it takes more than one day to complete a backup, but most days it only takes one day so this is mostly accurate!).

The GPFS file systems, main and data, are backed up nightly and ten copies are saved (if you never change a file it will always be available, but if you change it every day for ten days your changes before those ten days will not be available). The nbu filesystem is not backed up at all.


To request a restore please send email to Restore requests are queued and attended to within three days (we try to have them done for you as soon as possible). If there is a problem finding what you have requested, you will get a message requesting more information. It will speed the process up if you are as accurate about the window of time the restore can be done from as possible. Restores before August 2010 are no longer available.  When requesting a restore please remember the "10 copy" rule mentioned in the section above.

Snapshots (main filesystem)

The CS Department is in the process of migrating data from our old GPFS (General Parallel File System) file server to the University's Isilon file server. Both servers have a feature known as snapshots which allows for online file recovery of recently changed or deleted files. On GPFS, snapshots are enabled for the main filesystem, which includes the /course and /research directories; currently you can recover anything from the last three weeks. On the Isilon, which is currently hosting /home and /admin directories, snapshots go back farther. (Snapshots are not taken of the data or nbu filesystems.) See the "Using Snapshots" section below for docs on how this mechanism works and how to use it.

How do Snapshots work?

A snapshot is a read-only copy of all the files and directories in the filesystem. The server creates a snapshot every four hours. Snapshots can be accessed as quickly and easily as the live filesystem from the .snapshots (plural) directory in /course and /research, and the .snapshot (singular) directory in /home and /admin.

Snapshot directories on GPFS are named for the (GMT) time the snapshot was taken. We keep the most recent six snapshots, the last seven snapshots taken at midnight, and the last four snapshots taken at midnight on Sundays. This means that the live filesystem will have backups going back about a month. Snapshots on the Isilon are kept in a similar patter, extending up to six months back.

Using Snapshots

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