[Idea]: xattr support when using non-xattr storage

[InjectMeneer]

Hi,

After a lot of headache, I've finally been trying to find a solid solution to try and get TimeMachine working for an old QNAP with NFS or SMB, using this container on a far more powerful ODROID M1, but with a lot less storage.

I've been able to get it to work by creating an image using dd, located on a QNAP with an NFS v4 share, mounted on my docker host, using autofs. The mount has a bind to /opt/${TM_USERNAME}.

It's working as follows when using NFS (which is a lot faster than SMB on a QNAP):

1. Make sure the Docker host has mounted the shared volume using autofs, by choosing either SMB or NFS (I'm using NFS v4)

• /etc/auto.master.d/timemachine.autofs should contain something like: /host/folder/to/mount/autofs/nfs/shares/in /etc/auto.nfs --timeout=10 --ghost
• /etc/auto.nfs should contain something like: mount_name -fstype=nfs,vers=4.1,rw,soft,intr,bg NFS.HST.IP4.ADR:/NFS_share_name

2. Create an image file on the mounted volume dd if=/dev/zero of=/mounted/volume/on/host/timemachine_volume.img bs=1k count=1200 seek=300M. I've created a 300GB volume, which is thin provisioned.
3. Configure autofs to mount the image:
   • /etc/auto.master.d/timemachine.autofs add something like: /host/folder/to/mount/autofs/images/in /etc/auto.img --timeout=15 --ghost
4. sudo systemctl enable autofs && sudo systemctl start autofs
5. bind the correct folder to the docker container /opt/${TM_USERNAME}

TimeMachine should now be working flawlessly when configuring it. Be sure to encrypt the backups, though!

One could obviously create more docker instances, each with their own IP's, NFS shares/mounts and images, which isolates every instance even more.

If you've combined the storage server, and your docker host, on the same host, you should be able to just skip the first step all together. Just store those images locally.

I hope this helps the lot of people who are struggling with something like compiling fuse_xattrs and other flawed methods that just aren't a solid, nor working, solution.