Maximum Retention Policy


I wish Duplicati would add a retention policy that would allow users to set a maximum amount (size) of backups before deleting them. For example, the UI mockup would look something like this:

So if I have a 2TB drive to backup to, then Duplicati would fill it to the brim and only start deleting old versions once it is full.

If I backup to Backblaze B2 (with no size limits), then I could set a custom limit (say, 1000GB or 1.5TB, etc.) below the retention dropdown. Leaving it blank would allow Duplicati to follow the “Keep All Backups” retention policy (since it can’t calculate the total size of B2.)


There is some recent discussion of this in How to limit backups to a certain total size? (Uncategorized category) and some older discussion (plus coming partial step to this) under What does –quote-size? (Support category).


I agree that would be a nice feature, but as mentioned in the links above it does have some oddities including:

  • don’t know size until backup done
  • accidental huge file inclusion could cause all historical versions to be removed to make space