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Info Services > Computing Guide > Data Backup

User Shares Backup

Computer Back-up, Files, Storage

See also: File Access and Archiving, Network Access

Protecting Your Data

Desktops and laptops are not backed up unless you have made arrangements to do so. When your hard drive fails, your data may be lost.  Attempted restoration of data is time consuming, expensive and not foolproof.

To protect user data, regularly backed up Filer Servers are located at AOC, CV, and GB where users may store work-related files (called User Shares).  Check the site schedule below for quota information. Visitors should contact the local Helpdesk for assistance.

LocationServersBackup Schedule
AOC filehost (user shares)

Full and Incremental Backup Schedule



cvfiler (user areas)

Microsoft Exchange

Web servers

MySql database server

Full and Incremental Backup Schedule



gbfiler (mirrored user shares)

Full Daily Backup Schedule


Additional options for the individual user are to make regular backups to external hard drives, DVDs or tape drives. Please contact the Help Desk to set up a convenient backup plan to protect your work especially if your data backup needs are larger or more complex.

User Share Snapshots

The Network Appliance filer servers on which most of our Unix home directories live, have a very useful feature, one that is built into 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    nmstaff      323584 Oct 23 16:40 hourly.0/
drwxr-xr-x   79 krowe    nmstaff      323584 Oct 23 16:40 hourly.1/
drwxr-xr-x   79 krowe    nmstaff      323584 Oct 23 16:00 hourly.2/
drwxr-xr-x   78 krowe    nmstaff      323584 Oct 23 10:00 hourly.3/
drwxr-xr-x   78 krowe    nmstaff      323584 Oct 22 16:34 hourly.4/
drwxr-xr-x   78 krowe    nmstaff      323584 Oct 22 16:34 hourly.5/
drwxr-xr-x   79 krowe    nmstaff      323584 Oct 23 16:40 nightly.0/
drwxr-xr-x   78 krowe    nmstaff      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 can easily access these "snapshots" through the "Previous Versions" tab in Windows Explorer - see Accessing Filer Backups From Windows.

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.

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