Duplicati Does Not Recognize Files on Drives

Being as succinct as possible: I installed OpenMediaVault and Duplicati on a Raspberry Pi 4 4GB without any errors. I merged one 1tb SSD and one 256gb MicroSD card using SnapRAID and UnionFS to make an effective 1.1 TiB drive (I know it’s unconventional.) Everything is working perfectly as I mentioned. The Raspberry Pi has 2 users, the default pi user, and then another user used for accessing the shared folders on the system. The problem is that Duplicati does not see that files or the shared folders during the creation of a backup. The drives are mounted at /dev/sda1 and /dev/mmcblk0p1, but joined under the aforementioned UnionFS pool (pool1). Duplicati only sees the mount points as files. For example, in the mount directory, the drive mount would be seen as a file called sda1 under the /dev/ directory.


Is Duplicati running in a container on OMV? I think OMV calls them “plugins.” If so make sure Duplicati is running with sufficient permissions to access the mount points (that you have presumably already mapped to your container). Setting the PUID and GUID to zero so it runs as root may be an easy way to resolve this.

The linuxserver/duplicati docker image doesn’t run as root by default. The official duplicati docker image runs as root by default to make things simpler.

Thank you for the welcome! No. It is not running as a container. It was installed as a systemd service using a guide on this forum. Again, no errors occured during the install of the deb file. The apt repository was used instead of the deb file, with sudo apt install./[deb_file] issuing something like:

Notice: using "duplicati" instead of "duplicati_[version].deb"

Is there a point to switching to the official Docker image? I haven’t looked into that yet. I got Duplicati working in a previous install on a FreeNAS jail via running it as root, but I am not sure on how to do it on Debian (Raspberry Pi OS Buster).

No, you can install it directly on the OS if you wish. Can you confirm that it’s running as root?

I am not sure on how to do this. However, I have the following groups listed on my system:

pi adm dialout cdrom sudo audio video plugdev games users input netdev ssh gpio i2c spi

I will try using the following in the unit file under the [Service] section in addition to what I have:


However, I will try without the Group declaration first, as the root user maps to root:root in the groups command.


Using Group=root in the unit file breaks pretty much everything. A lot of the dropdowns don’t work, and the speed limiter becomes broken.

Hmm you shouldn’t need to put that in your systemd file. I checked mine and it doesn’t specify User or Group, and Duplicati definitely runs as root. Set the file back to the way it was originally and restart it using systemctl.

Try this to see if Duplictati is running as root:

ps aux | grep -i duplicati

On my system I see:

Ok. It was running as root this entire time.

Ok, if you bring up a shell prompt as root, can you navigate to and see the files?

I got it working now. The problem was with my OMV configuration. I had the ACL as “Administrators: None, Users: read/write, Others: None”. This meant that root couldn’t access the drives. Thanks for your help.

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