Backup not working correctly (missing files)

Support
#1

Hello,

it seems im off to a bad start with Duplicacy.

I created a Backup from my /mnt/ssd which houses the disk image files (.qcow) of a few virtual machines.

The backup went through and I did not get any warning/error whatsoever.
The backup was very small though (9GB whereas the original files where 25G). So i ran it once more (running the backup from the “Backup” tab, not scheduled). Now it is ~10GB.

I decide to run a restore to another location just to make sure everything is fine … which it isnt.
The largest disk image is missing. Another disk image from the same directory was backed up though. I do not have any exclusions set.

How can I debug this? And also: If a backup somehow fails I expect a warning in big fat red letters in the WebUI. Ist that a wrong expection?

Thank you
Daniel

#2

Duplicacy (or any other software) cannot backup files that are open in exclusive mode, like running virtual machines are. Was your virtual machine running at a time of backup?

You can work around that by creating a disk snapshot and backing up that snapshot instead. On Mac and Windows Duplicacy supports that automatically with -vss flag.

However doing so will have questionable outcome. Unless you coordinate with the guest to flush caches you will end up with inconsistent image in your backup.

Consider Instead of backing up your VM backing up the data VM operates on.

1 Like
#3

ok, that makes sense.

however, shouldnt there be some warning that files x,y and z were not backed up? That seems very dangerous?

#4

There is. In the backup log.

And it is not dangerous; that is not a fatal event to make a big fuss about in the UI for example. A bunch of files are expected to fail to backup for various reasons — for example, contents of your ~/.ssh keys if Duplicacy is not running under your user account, or any open document if you are not snapshotting the filesystem (e.g. manually in prebackup script if needed)

It may be however useful if Duplicacy showed brief stats on each backup run in the activity page — like «69 new files backed up, 29 skipped». Maybe it already does it — not sure.