Resiliancy with periodically attached backup location

I use CrashPlan for my backups currently because it allows me to nominate a USB drive as a backup location but does not error if the drive is not available. Instead, when the drive is attached, it does a compare and updates the backup set at that time.

I use this for my offsite backup, as I can attach the USB drive when appropriate and then safely house the USB drive elsewhere after the backup is complete.

Duplicati appears to offer this functionality, but is it as simple as just periodically plugging in the USB drive and having the app automatically update the backup set?

No. Backups from the GUI are either scheduled or require starting with Run now button.

One way to have scheduled backups sort of do this is to only backup if drive is present.
(also available in your Duplicati installation) shows how the exit code can cause a “don’t run” of a backup.
Scripting options such as run-script-before would be used. As usual, don’t remove drive during a backup.

offers another solution which might be closer to your instant start. To integrate with the GUI (which can be simpler to use for operations such as restore) you can Export As Command-line, and run from that event.

Device mount detection (USB or otherwise) has other ideas as well, and I can’t say which is best for you.

If you want multi-drive rotations, your life gets more complicated. A backup job is paired with a destination, however there are some ways to handle it (and several forum posts) if that becomes necessary for you…

Thanks @ts678, that’s obviously more complicated than CrashPlan, but not critically so.

I am not sure what your term ‘multi-drive rotations’ refers to, though. Do you mean a back up set saved to multiple destinations in some kind of round-robin sequence? If so, my requirement is - I think - simpler:

  • All files being backed up are sent to the same destinations (one cloud, one NAS, one USB drive) as one backup set.

My aim is destination redundancy and once configured and scheduled, Duplicati would execute with the only further action being a restore in event of a ‘disaster’.

My read of the manual was that Duplicati can be configured in this fashion, but based on your reply I will need to drill in and confirm.

A simple multi-drive plan would have two drives in rotation so there’s always one off site backup.
Your plan achieves that in a different way. About the manual, feel free to cite and quote if needed.

sounds like you’d like it all to be automatic. I don’t think Duplicati ships that way. I might be wrong.

Back up external hard drives for current CrashPlan might provide the appearance of that by using scheduled backups (as opposed to connect-time start) and doing graceful disconnect/reconnect.

Duplicati “should” be able to survive USB disconnect (if drive does), but likely reports it as an error.
Interrupted backup should continue its progress on next run, but letting runs complete is preferred.

If you don’t mind errors, out-of-box Duplicati can approximate what you wish by scheduling frequent backups (minimum is 5 minutes) and relying on its file list compare next run. It would then continue.

I recommend not unplugging USB drive mid-backup though. You’ll have less noise and other issues.

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