Setting up retention/versioning with Backblaze B2?

What with crashplan planning to no longer support personal users, Duplicati seems a great option, especially as it has gui. Thanks for the hard work on developing it.

I plan to use Backblaze B2 with Duplicati. Though I’m not sure how best to set up rentention/versioning/pruning.

For example, I have a large video folder (400gb), it doesn’t change much, say a couple of files added every 1/2 weeks. On B2 cloud storage, I would not want to keep multiple whole versions of this folder (due to its large size).

On the General Options, would it be sensible to set: ‘Keep this number of backups’ ‘until they are older than’ ‘1 Month’?

TBH, I don’t fully understand how this works. Is an initial (compressed, encrypted) backup of the video folder created, then incremental changes are added. What happens after 1 Month?

Any advice and further explanation will be appreciated

After a full initial backup, Duplicati will upload only newly added files or the changes in existing files.

1 month here refers to the amount of time for which deleted files and previous versions of modified files are kept on the backup destination (Blackbaze) before being deleted by Duplicati. Selecting a month would mean you will be able to restore any file accidentally or otherwise deleted in the last month. Same for a previous version of a modified file too.

Unless you frequently delete very large files from your folder, I think it’s o.k. to use a larger retention period such as 3-6 months.


Thks for the helpful information.

I’m not sure you know about Backblaze B2, as I noticed it has its own retention policies that can be set for a bucket. I’m assuming it’s best practice to leave it to the default of ‘Keep all versions of the file’, and let Duplicati take care of things?

You don’t need Blackblaze’s versioning since Duplicati implements its own. Just use a separate bucket for Duplicati with the option Keep Only Last Version.


So, you should not leave Backblaze at the default “Keep all Versions” then?

I never thought about changing this. With Duplicati set up for unlimited backups, is there any particular reason to change the lifecycle settings at Backblaze (better use of storage space, etc.), or is this just a personal preference? And am I to assume changing the bucket lifecycle settings later on would have no negative effects on your backup (I’m guessing it wouldn’t, but you know what they say about assumptions…).

Keeping the default Keep All Versions option selected will not adversely affect your backups.

As for changing the bucket’s lifecycle, I too would assume that it does not affect your backups. Any sensible implementation would either

  • Stop versioning from this point forward but keep previous versions or more likely
  • Remove all old versions of files but keep the current versions.

Since neither of these would have any effects on current files, which are the only ones duplicati cares about, you should be fine. But just to note again, this is based on an assumption.

You could verify B2’s behaviour in a separate bucket. Or you could just leave everything as is. Since you have already set duplicati to keep unlimited backups, there should be very little unwanted data in your bucket (deleted by duplicati, but versioned by B2).

But it will affect your wallet, since anything you evee upload will stay there (and take up space), won’t it?

Oh yes, absolutely. As I mentioned earlier, it would be best to first test changing lifecycle settings on a separate bucket and then, if everything goes as expected, change the setting on the backup bucket.