Is this urbackup-docker in a VM or an LXC? If the latter, you don’t need to add it in storage at all; you can bind mount the folder and use it directly. Here’s some info on that. If it’s in a VM and you want to use the directory directly (as in not just make a disk image inside the directory to pass as a block device) you’ll have to do some file sharing to the VM.

It sounds like you’ve got your solution already, but just in case someone stumbles on this later, I thought I’d mention autofs.

I’m coming to prefer it over fstab entries because it handles disconnections nicely and attempts to reconnect. Worth checking out for those who haven’t played with it.

Could be. If that’s the case, it’s nothing I’ve noticed. I’ve got a 32gb VM and I’m running a bunch of LXC and docker containers on it without issue.

I’ve never heard anyone else mention them, but I’ve had really good luck with https://www.ssdnodes.com for the past several years. I don’t recall ever using their support, but I did have a policy question before buying when I first signed up and they were pretty quick to reply. I think I found them on LowEndBox.