Ubuntu – How to change output device for backups

It looks like Déjà Dup keeps at least two full backups before it will free up space by overwriting old ones. You mention you have been using it for a 'couple months'. I bet that means you are up against this limitation. Full backups can't be scheduled exactly, but it is going to be about once a month with scheduled backups happening weekly.

You can manually delete old full backups, they are all those 'duplicity-full*' files on the backup drive. Make sure you have at least one full backup to recover from, obviously. You are taking a risk here that your remaining full backups are not corrupted, too.

Best practice before deleting anything is to use another drive to make a tested, known good backup to, then try deleting and/or resizing the backup partition on the destination drive.

Since you know you normally need 2 backups before Déjà Dup will make the third (and overwrite older ones), you need a destination of roughly 3x your current quantity of data being backed up.

If you are seeing different behavior or any bugs, you can ask a question or report a bug on the project's Launchpad page (requires a Launchpad account)

It's very easy to do this, don't worry.

1. Navigate to the folder where your backups are
2. CTRL + A To select all files
3. DELETE To delete all files

A couple of observations about the files in the backup folder, in case you don't want to delete all backups:

All files can be identified as part of a full or incremental backup. Look for 'duplicity-full...' or 'duplicity-inc...' at the beginning of the file names, where the arrows are pointing in the image above.

All files can be identified by creation date in the filename, like the highlight at top left. The format is YYYY/MM/DD.

Most files in the backup directory will be simple archive files, like in the top row of the screenshot. Highlighted in the middle and bottom rows are the other two files created per backup, 'signatures' and 'manifest'. For each backup you will have many files like in the top row, and one each like in the middle and bottom row.

To delete a specific backup identify all files by date in the filename. When working in a directory deleting things, make sure you have at least one more copy elsewhere, in case you delete the wrong thing by accident.