[genius]

Restoring Data from rdiff-backup

Once you have a backup directory, you can quickly display a listing of the increments available. An increment is some previous date for which exact files are available. Whenever you run rdiff-backup, the current mirror is updated and a new increment is created, still allowing you to retrieve the previous set of data. Here is an example listing of increments:

% rdiff-backup -l /some/backup/directory
Found 4 increments:
increments.2003-01-02T23:30:45-04:00.dir Thu Jan 2 23:30:45 2003
increments.2003-01-03T23:31:40-04:00.dir Fri Jan 3 23:31:40 2003
increments.2003-01-04T23:31:54-04:00.dir Sat Jan 4 23:31:54 2003
increments.2003-01-05T23:32:02-04:00.dir Sun Jan 5 23:32:02 2003
Current mirror: Mon Jan 6 23:32:18 2003

There are two ways to restore data from an rdiff-backup archive. One is to look through the data and run rdiff-backup on one of the increment files. The second method is to use the –restore-as-of(-r) switch.

Let's assume that the backup archive shown in the previous increment listing was created by the following backup script, executed at around 23:30 every day:

rdiff-backup /etc /some/backup/directory

Now, assuming it is Tuesday at 16:00, and I want to restore the /etc/ directory as it was yesterday at this time, I would run the following command:

rdiff-backup -r 1D /some/backup/directory /tmp/etc.old

Since no backup was performed exactly one day ago, the next oldest increment is used. In this case, that would be the backup performed on Sunday night (2003-01-05T23:32:02-04:00). I could also have specified this full date string instead of 1D as the argument to the -r switch.

The exact state of the /etc/ directory when that backup was performed is now re-created in the local directory /tmp/etc.old/. You can then do anything you would like within this temporary directory.