How to specify "--link-dest" on server (rsyncd.conf)?

Carl E. Thompson lists-rsync at
Sun Apr 20 17:02:58 GMT 2008


    This is my first post to the list.

    Is it possible to specify the --link-dest option server-side in the
rsyncd.conf file? What I'd like to do is implement incremental snapshot
backups without having to change the clients which all just do regular
dumps to the rsync server. I'd like to specifiy this option on the
server rather than on the client because I don't want to have to change
all of the clients and don't want to trust that all of the clients are
configured correctly. So in essence I'd like the clients to think
they're doing a regular backup to a "write-only" module in whatever way
they see fit but I'll have script magic on the server that makes it an
incremental snapshot. I can accomplish this imperfectly by using the "cp
-al" hard link method but this is vulnerable to permission / owner /
group problems that could easily compromise all of the snapshots. It
seems to me the easiest way to do this would be if it were possible to
specify the "--link-dest" option on the server side in the module
configuration in the rsyncd.conf file. This would either override the
option if specified on the client or error out.

    Alternatively and best of all I could accomplish the same thing with
the "cp -al" method if there were an option to tell the server that
permission / owner / group / other changes are never to be performed
directly on an existing file but that a new file is always created via
local copy and moved into place (such an option would of course conflict
with options like "--inplace"). This would be a valuable option to have
because it could help guarantee for a paranoid administrator that
previously backed up and hard linked files won't be modified by rsync in
case of a configuration error or malicious client.

     If there is no way to do either of these things with current
versions of rsync how would I go about requesting this feature for a
subsequent version?

Thank you very much,
Carl Thompson

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