symlinks that become directories question

[rob at mangiafico.net]

On Tue, 30 Oct 2007, Matt McCutchen wrote:
> On Mon, 2007-10-29 at 13:15 -0400, rob at mangiafico.net wrote:
> > If I have a backup script that does the following:
> > (latest 2.6.9 rsync)
> >
> > rsync --archive --hard-links --force --ignore-errors --numeric-ids
> > --keep-dirlinks --delete / /backup
> > 
> > I've found that if there is a symlink in place that gets backed up 
(which
> > goes fine), i.e.:
> > homelink -> /home/
> >
> > and then that symlink gets changed into an actual directory, i.e.: 
> > rm homelink
> > mkdir homelink
>
> I assume this directory is empty?

Yes.

> > rsync will actually delete everything in the directory that the 
symlink
> > pointed to (in the above case it deletes /home).
>
> Rsync's behavior, however surprising, is correct.  Since you passed
> --keep-dirlinks, rsync is mapping the source's "homelink" directory to
> the target directory of the destination's "homelink" symlink,
> i.e., /home.  (Without --keep-dirlinks, rsync would first replace the
> destination's "homelink" with an actual directory.)  Since you passed
> --delete, rsync deletes any and all files from /home that lack
> counterparts in the source's "homelink".
> 
> > Is the workaround to use --delete-after to avoid this behavior, or is 
my
> > logic flawed in using rsync with the command above to produce a mirror
> > copy of an entire server to a backup drive?
> 
> --delete-after gives the same behavior.  To stop rsync from following
> the destination's symlink to /home, you will have to remove
> --keep-dirlinks.  Unfortunately, if there are other dirlinks that you
> *do* need to keep, you will have to do something more complicated.

Thanks for the explanation. Since all we're doing is using rsync to make a
backup on a second drive, and this backup will be used for either
file/directory restores, or in the event of a primary drive failure, used
in a bare metal restore situation, I believe leaving off "--keep-dirlinks"
will not cause any problems, as the symlinks that point to directories on
the primary drive will still be intact on the backup drive, and can be
restored "as is" on a restore, correct? We don't need rsync to follow the
symlink, as we're already backing up all the data on the OS.

Rob