Network Backups in Socorro



All user data that lives in /users/USERNAME is backed up every day at 8:00pm MDT. These backups are incremental with a full every Friday.

Snapshots - what are these and where?

The Network Appliance "filehost" file server on which most of our Unix home directories live, has a very useful feature, one that is built in to its fundamental native file system (WAFL). This feature, known as "snapshots", is available from both Unix/Linux and Windows systems. The effect of the feature is to provide you, the user, with a read-only snapshot of how your files looked at a particular moment in time.

In your Unix home directory on the filer, there is a directory called .snapshot. If you browse it (either from the command line with cd and ls, or using a graphical explorer-like interface such as with Gnome, KDE, or Windows), you'll see several sub-directories therein, perhaps something like this:

paso krowe > cd .snapshot/
paso krowe > pwd
paso krowe > ls -l
total 2560
drwxr-xr-x   79 krowe    staff      323584 Oct 23 16:40 hourly.0/
drwxr-xr-x   79 krowe    staff      323584 Oct 23 16:40 hourly.1/
drwxr-xr-x   79 krowe    staff      323584 Oct 23 16:00 hourly.2/
drwxr-xr-x   78 krowe    staff      323584 Oct 23 10:00 hourly.3/
drwxr-xr-x   78 krowe    staff      323584 Oct 22 16:34 hourly.4/
drwxr-xr-x   78 krowe    staff      323584 Oct 22 16:34 hourly.5/
drwxr-xr-x   79 krowe    staff      323584 Oct 23 16:40 nightly.0/
drwxr-xr-x   78 krowe    staff      323584 Oct 22 16:34 nightly.1/
paso krowe >

Within each of these hourly or nightly snapshots is a complete copy of how your files appeared at that time. This is a read-only copy, meaning you can browse the files, and/or copy them to "normal" (non-snapshot) locations such as your real home directory, but you cannot write to them, nor can you manually place files in the snapshot directories.

Windows users cannot easily browse these directories from an explorer window by clicking, but the files and subdirectories are there; you may have to enter the directory explicitly (by typing it in, e.g. via the RUN command from the START menu).

While it may appear that we're wasting huge amounts of space with these snapshots, we're not, really. The "WAFL" file system on the NetApp is constructed in such a way that the snapshots are like incremental backups; they really only contain the changes and differences -- at the disk block level -- between your current files and how they appeared at the time of the snapshot. If the file hasn't changed, they'll be identical and take up no extra space.

Automated Backups

AOC Computing Infrastructure Department provides backup services for a small number of mostly centralized systems. In general, you should assume that your desktop and/or workstation disks are not routinely backed up, unless you are told otherwise.


We operate a Network Appliance "filer" called filehost, on which is stored most of our home areas, and a whole lot more. We have an LTO-5 jukebox to do backups. Full backups are performed every Friday starting at 8pm. Incremental backups are performed every day except Friday at 8pm. We use the Networker software from EMC.

This, plus the snapshot feature described above, provides us with a good solid backup regimen for our critical files. NOTE: most users have a quota of 16GB in their home areas on the filer; contact the helpdesk if this is not enough for your needs. And remember, your backed-up-home-area on the filer is not intended for bulk data (FITS files, measurement sets, AIPS or CASA data, etc)!


See Backing Up Data in the AOC Computing Help pages for instructions on backing up your files yourself.

Content reviewed on: 12-Jul-2012
Reviewed by: krowe

Last modified on Monday, 01-Dec-2014 16:01:40 MST