How to switch from 7z to zip in already existing backup scenario?


Kenkendk wrote about some problems with 7z. So now I have already backed up lots of stuff with 7z. I do not want to delete anything and re-backup. Should I do it? Or can I change the backup set option and then get a mixed backup which slowly converts to zip over time…? Is that possible?


In principle it should work, but it requires that you have full churn (i.e. that all your files change) otherwise you will be stuck with at least some 7z files.

I would recommend starting over, even though it may suck.

This task: It’s almost impossible. I deleted the backup folder on Google drive. I started backup: does not upload anything. I deleted+repaired database: it tells me “No files were found at the remote location, perhaps the target url is incorrect?”

Do I really have to export configuration, delete config, import configuration?


I’ve done this a couple of times (wanted to change folder names in B2 which is impossible) – it just takes a lot of trying between deleting data & repairing & trying something else when that doesn’t work. The fastest way, if you’re deleting and starting over anyway, might just be to export your config and re-import using your new preferred parameters.

Also: it sounds like it might already be too late, but what I was originally going to suggest was to change your volume size to something a bit bigger and then run “compact now”. From what I’ve seen, that might download, re-pack, and re-upload every data volume in your archive if you let it (and should be fine if you don’t have to worry about download bandwidth… not suggested on B2 unless you really really need it… should be fine on GDrive though).

1 Like

Is this a problem with the storage (B2) ?

It should just be a matter of editing the destination url, and then moving the files (using the B2 webpage).

Duplicati does not store the destination path, so it should cause no problems if you move files from S3 to B2 or a local disk, as long as all files are there.

B2 doesn’t allow

  1. files to be moved between folders, or
  2. folders to be renamed

in any way that I could find. At least not via the web interface.

When I did my first B2 test run, I dumped the files straight into a bucket without putting them into a folder - I quickly regretted that, but there was no way to fix it directly. I had to delete, create a folder with a “temp” name (mistake), then re-run my backup. Then when I wanted to move away from the “temp” name on that folder… oops, can’t rename folders. Had to re-do again. The good news is that it’s all done now, no harm no foul.

If the uploaded 7z files are verified (after a compact command is run, if auto-compact is enabled), wouldn’t this be okay? E.g. all new files/blocks uploaded would be .zip, and the old 7z files were not corrupted?

However, is there actually a way to verify all files currently? As I understand it, the verify files option just checks that the already encrypted blocks exist and match hashes, not the actual contents, so it wouldn’t be helpful. How about repairing / recreating the database - would that expose any corruption? Or Would the only way to truly verify files is to somehow attempt restoring at least one file out of every block?

Yes, in this case it should all be fine.

You can do this via the commandline, something like like:

Duplicati.CommandLine.exe verify all --full-remote-verification

This will download the files (check the hash as before) and open the zip or 7z files and attempt to read and verify the contents of the files as well.


If one REALLY wanted to change compression settings (such as 7z vs zip) of existing files, would it work to fiddle --small-file-size, --small-file-max-count and possibly --threshold such that every file would be considered small so would be downloaded, re-compressed with the new settings, then re-uploaded?

Isn’t that what the RecoveryTool’s recompress option does?

1 Like

Sure, if you want to do things the easy (aka correct) way! :blush:

Thanks for pointing that out, though not everybody is CLI capable. Though honestly I haven’t poked through the GUI to see if it’s available there at all.

The RecoveryTool.exe is not available from the GUI. I think it is a fairly “expert” tool.

1 Like