[rdiff-backup-users] sshfs: workaround and test results

[Andreas Olsson]

Here comes the results of me testing rdiff-backup 1.1.15 with sshfs.

Surprisingly not it didn't take long for me to run into this issue.

http://lists.gnu.org/archive/html/rdiff-backup-users/2007-08/msg00086.html

Luckily there is a workaround in sshfs you can apply (-o workaround=rename)

Perhaps that sshfs-workaround should be mentioned in rdiff-backup's 
documentation? Myself I plan to write a page on sshfs in the wiki, but as for 
the official documentation, that is for someone else to decide.

Anyhow, with that workaround all the tests I have run against a sshfs-mount 
have worked really well. No errors to report.

Obviously sshfs couldn't create hard links. They were instead stored as 
separate files. Perhaps information on hard links could be saved as metadata 
and then the hard links would be recreated on a restore?

I also took the opportunity to do some performance test comparing running 
rdiff-backup against an sshfs-mount and running rdiff-backup the "normal" way 
through an ssh-tunnel. In those cases which primarily involves transferring 
files, such as an initial backup or a restore, it always took conciderable 
longer time when sshfs was involved, no matter the amount of files, the speed 
of the link, etc. When doing an incremental backup, in other words mostly 
comparing files, updating metadata and transferring a few files, the results 
vary depending on the changes in question, the speed of the link, etc.

(No I don't feel I have enough data to be more specific then that.)

These tests have primarily been performed using the latest stable release of 
sshfs (1.9) and fuse (2.7.2).  I have also done some testing using the 
slightly older versions included in Debian stable (etch).

-- 
Andreas Olsson
http://www.andreasolsson.se/

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