rsync - Apr 2008 - How to specify "--link-dest" on server (rsyncd.conf)?

Hello,

    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

Hmm... I didn't get any response to my post... did I send my question to
the wrong list? Is there a more appropriate way to contact the rsync
developers? Did I miss some feature in the documentation that does this?
Are the developers simply too busy / not interested in responding to
this issue? Please steer me in the right direction if there is anything
I'm doing wrong with my request.

Any type of acknowledgment at all would be appreciated!

Thank you,
Carl Thompson


Carl E. Thompson wrote:
> Hello,
>
>     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
>
>

I didn't read all of your post, to be honest, so forgive me if this does
not help, but are you aware of rsnapshot <http://www.rsnapshot.org/> ?
It is very nice for snapshots and uses rsync 'behind the scenes'.

Search the list archives for info on this. In particular, this post
<http://lists.samba.org/archive/rsync/2007-December/019470.html> comes
to my mind which deals with a situation similar to yours (if I haven't
misread your description): rsync daemon on server, no changes on  
clients,
clients "push" backups to server, server handles snapshots.

-Moritz

Am 20.04.2008 um 19:02 schrieb Carl E. Thompson:
>
> Hello,
>
>     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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