Is there a way to backup/snapshot Docker volumes?

Apps and Virtualization
1

I manage my Docker containers manually via Dockhand.
For persistent storage I mostly use bind mounts which I map inside ZFS dataset where I can set automatic snapshots.

I was thinking about using Docker volumes which are little more integrated into Docker management.
But since its meant for persistent data it must be backed up and I cant find a way to do it.

On TrueNAS, Docker volumes are stored inside hidden .ix-apps ZFS volume, specifically /mnt/.ix-apps/docker/volumes.

From what I see, this is configured globally for Docker, so all Docker volumes go there and it cant be changed.

Since this .ix-apps is hidden, I dont see any way to snapshot or backup Docker volumes inside, which is dealbreaker for persistent data.

For context, in the official TrueNAS Apps there are two main ways to save persistent data, Host Mount and ixVolume. Both are Docker bind mounts underneath. The ixVolume has confusing name because its not actually Docker volume.

So, since official TrueNAS Apps dont even offer Docker volumes, should I presume Docker volumes are not officially supported and there is no way to snapshot/backup them?

Thanks.

2

yeah thats basically it. named volumes on scale sit under /mnt/.ix-apps/docker/volumes on the hidden ix-apps dataset. you can snapshot that dataset from the cli (zfs snapshot pool/.ix-apps@whatever) but it is not in the GUI dataset list on purpose, and replicating .ix-apps is a mess because the apps service owns it.

if you actually care about the data, keep bind mounting to a normal dataset like you already do. official apps do the same (host path and ixVolume are both bind mounts). named volumes are there because docker wants them, not because ix wants you using them for persistent stuff.

3

I avoid docker volumes by default.

Just like nite said, take matters into your own hands by using specific docker binds to your data.

It’s truly a shame that IX systems delivered THIS, and could not deliver an easy, transparent, logical way to backup your apps!