remote backup options

Lennart Sorensen lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at
Tue Sep 22 22:31:53 UTC 2009

On Tue, Sep 22, 2009 at 06:20:12PM -0400, Darryl Moore wrote:
> I think you'll have to explain yourself here. It communicates with the
> remote server via rsync. Rsync was designed to be efficient at
> replicating files over a distance.

Yes but I don't think rsync has an option for doing what rsnapshot wants
to do, which is rename the last target, then run with that renamed target
as the hardlink source for unchanged files while rsyncing a new target.
That is what rsnapshot does.  rsync certainly can do it when the
destination and previous target are on the localhost, and the source of
the rsync files is the remote machine.  I don't think it can do it in
the other direction, although it might.

> don't you know? You said you used it a lot.

Yes but I also run debian stable on servers, which means using whatever
version of rsnapshot it includes.

> What is the problem that needs solving exactly? I believe the server
> only needs to run rsync in server mode. The rsnapshot utilities are run
> on the system to be backed up.
> Are you still sure we are talking about the same thing?
> Then why did you say "Well if the remote offers you an NFS mount, then
> it might work ok."?

NFS would at least be a disk allowing the rename and hardlink trick to
be treated as local that I know rsync supports.

Specifically rsync's --link-dest option takes a directory, not another
remote rsync target.  That's what makes me think rsnapshot can't do that
to a remote box, while rsnapshot can pull from a remote box.  It would
be a nice setup to configure rsnapshot on a backup server to pull the
backup data from all the clients machines to a central spot, compared
to configuring each client to try and push their backups to a central
backup server.

Of course the fact the rsnapshot config file always shows a local
filesystem as the backup target, and has lots of ways to specify local
and remote machines as the source for the files seems to backup my
understanding.  That's from version 1.3.x though, not 1.4.x.  Checking
the man page for the current version doesn't change that part though.
The target of the backup is always a local disk, while the source can
be local or remote.  Hence the only way to use a remote storage would
be to treat it like a local disk, such as with NFS (which is a bad idea
in this case).

Len Sorensen
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