How do you resume a backup

I was running a backup for around 1.5TB of data. I got to around 40%, but it was taking forever so I thought I’d pause it and restart my server (this was to reset some power configurations). For some reason, pausing the backup wasn’t working in Duplicati, so I stopped the container, restarted my server, but upon starting the Duplicati container, the backup isn’t automatically resuming.

In the Restore tab, my backup is listed with the description “Unknown backup size and versions”.
If I go back to the Home tab and run the backup, it spends a while “counting”, then starts backing up the entire 1.5TB again. There should only be 800-900GB left to back up, so why is it starting from the beginning again?

Is there anything that can be done at this point? The backup destination directory still has like 600-700GB of data in it; why can’t Duplicati just resume from there? On top of that, I’m now getting the message “Failed to connect: The database file is locked database is locked” when I try to restore from that directory.

You can’t pause a backup and expect it to survive an application restart. This is not a Duplicati feature. When you pause a backup, you can only restart it, and if you want to restart/stop the computer/container/whatever, stop the backup. It will then finish its operations, record where it has left, and stop. So when you restart your computer/container/whatever, running the backup again will take the already backed up data in account.

is the database in the container ? If yes, it should have been closed when restarting the container. If not, well, who knows ? Probably restarting the whole computer could fix it.

Automatic start-a-backup-at-Duplicati start is only on overdue scheduled backups - but gets complaints. Sometimes an automatic start gets in the way of other things one might want to do, for example restore.

It’s not, but it does need to know if any other changes were done while it was away, so it scans Source.

I’m suspecting it did. If you were watching the Destination files and uploads, please say what you saw. Chance of it tossing that data are roughly zero in my opinion, but more uploads would delay for awhile.

Did you let it finish its backup before the restore? How exactly was restore tried? There are many ways.