Time-Machine backup over SSH tunnel to NFS mount

Question

I've recently started using a new NAS which runs CentOS 6.2. One of the purposes of the NAS would be to serve as a backup target. Whilst I have been using Apple's Time-Machine for a while and I am very satisfied with it, I'd like to continue using it.

Backing up directly to an address in my network is no hassle; all works fine.

For security reasons I'd like all my traffic to go through an ssh tunnel to the NAS. This way I can avoid needing to get a VPNserver (for personal reasons). As of NFSv4 the NFS deamon is bound to port 2049, which makes it easy for me to direct all traffic through a ssh tunnel.

Tunnel:

ssh -f admin@ms -L 2000:localhost:2049 -N

Mount:

mount -t nfs -o nfsvers=4,rw,proto=tcp,sync,intr,hard,timeo=600,retrans=10,wsize=32768,rsize=32768,port=2000 localhost:/mac_backup /Volumes/backup

This works fine for Finder/terminal and throughput is almost equal to direct traffic. (CPU of the NAS does ride high when I reach max bandwidth though)

Now the problem: With Time-Machine I can't use the NFS mount point mounted on localhost. TM seems to try to connect to it and then give me a "OSStatus error 65".

I also tried using NFSv3 (I correctly forwarded all ports) with no luck.

Can anyone shed a light on this and/or give a solution?

Answer 1

This blog entry has some of the best information I have seen so far on this question:

Mac OS X Time Machine via NFS on Linux Ubuntu (Complete Guide, fixes error 13, etc)

The short version: you need to create a "disk bundle" that Time Machine will recognize as a valid backup file, and transfer that to your NFS server (your NAS in this case). Once this is done, open the NFS server under Time Machine and your backup should be performed correctly from now on.

Please note that I haven't tried this yet – but I fully intend to. Also, it is Ubuntu-oriented, but most of the commands should apply to your Centos NAS just fine.