Backups And Restores

Getting Lost Files Back

You can only get files back which were present When Backups Are Made. In many (but not all) cases, this boils down to the file being present on the system overnight.

On a UNIX System

The first thing to try is the /s/std/bin/recover command. Change to the directory that the lost file(s) used to be in and enter the command recover list . Recover will either give you a list of files that it can restore or an error message stating that it cannot recover any files. If you see the file(s) you wish to recover in the list, use the recover fetch filename command, replacing filename with the name(s) of the file(s) you wish to restore. Keep in mind that recover can only restore files from the latest version of your AFS backup volume. For further information, take a look at How Backups Are Made .

On a Windows System (or unable to use recover command)

Use the Restore Request form. This method will allow you to submit a request for the CSL to restore your file(s) from older backups. Please fill in all of the information as completely as possible. The Systems Lab will attempt to complete the restore within one working day. Some restores require accessing offsite storage and will require more time, but they will be processed as soon as possible. You will be notified by electronic mail when your file(s) have been restored.

Restoring Files From A Previous(removed) Account.

If your account has been removed, and you wish to have the data restored (either for use in a new account or for saving to other media), you will have to come to the Computer Systems Lab office (room 2350 CS) and complete an Account Recover and Archive form. There is a $25 charge for restoring data from closed accounts.

We will make every attempt to restore your data although results can not be guaranteed, especially for older data.

Restore Request

Before you request a restore, make sure you have checked Getting Lost Files Back which can be found above. If you are still unable to recover your files then proceed to the authenticated CSL forms page and the restore request form.

What Are Backups?

Backups are the process of saving copies of the files on the system for use in an emergency. The Computer Systems Labmakes three types of backup tapes:

• Incremental Backups: are made every day, of all files that have changed since the previous incremental backup
• Epoch (Full) Backups: are a complete save of every file on the system.
• Semester Saves: are Epoch (Full) backups that are saved at the end of each semester

How Often Are Backups Made?

• Incremental backups are made every day
• Epoch (Full) backups are made of each system once every two weeks
• Semester Saves are epochs (full backup) saved at the end of each semester (Spring, Summer[AFS user volumes only] and Fall).

How Long Are Backups Saved?

• Incremental backups are made every night, and are saved for one month.
• Epoch backups (complete backups) are made twice a month. The first set from each month are saved for one year. The second set from each month are saved for one month.
• Semester Saves (complete backups made after the end of each semester) are saved for two years.

When Backups Are Made

The Computer Systems Lab makes backups of all Unix systems every day. Backups start shortly after midnight, and usually complete by 6 AM.

It is important to understand some of the details of How Backups Are Made in order to understand what files may be restored from tape.

How Backups Are Made

AFS Backups

The AFS filesystem provides a mechanism called backup volumes. A backups volume is a snapshot of a regular volume, with an exact copy of all the files that are in the original volume (actually, the backup volume doesn't really have copies of the files at first, so it doesn't take up extra space). Once the snapshot is made, if you modify a file in a volume, the change is only made in the regular volume, and the version in the backup volume stays the same as it was when the snapshot was made.

The Computer Systems Lab make a snapshot of every volume shortly after midnight every day. Incremental and epoch backups (see What Are Backups? ) are made from the backup volume. This means that a file from an AFS volume can only be restored to the state it was in shortly after midnight, when the snapshot was made.

The other advantage of backup volumes is that users can get back yesterday's files immediately. If you want the version of a file as of midnight, use the recover command. If you want to restore a file that is not in the snapshot (a file from a previous day), you will have to use the regular Restore Request.

Non-AFS Backups

Files that are not stored in the AFS filesystem are saved to disk directly from the filesystem. In order to be saved, the file must exist at the time When Backups Are Made. The exact time is not predictable.

Files on windows workstations are not backed up. If you want your files backed up, keep them in the AFS file system.