Re: duplicity backups are unidirectional? : local_directory -> remote_host

[Andrew Reid <reidac@bellatlantic.net>]

[About remote back-ups w/ duplicity vs. rdiff-backup]

  I am unfamiliar with duplicity, but use rdiff-backup regularly,
as well an rsync/rsnapshot combination.

  One thing that I like to do is to separate the remote transport
from the actual back-up process -- there can be performance penalties
for this, but it gives you better control.

  For instance, since you mentioned encryption, for your first
scenario, you could make an sshfs mount of the remote filesystem 
on the back-up host, and then run duplicity (or another tool) in
local-to-local mode.
  The performance penalty arises because the back-up tool now
has to scan the source file system for changes over the 
network link, rather than running a daemon at the far end
to scan it locally.  Depending on the speed of your link
and the size of your filesystem, this may or may not be
a problem. 

  I do this in production (with rdiff-backup, not duplicity) with 
a machine that actually backs up from a remote to a different 
remote -- the "source" remote is a read-only NFS mount, which
therefore appears local, and the "target" remote is an iSCSI 
target on a storage appliance, which also appears local.  
The performance penalty is real, but it works for me.

				-- A.
--
Andrew Reid / reidac@bellatlantic.net