[Samba] Circular links and backups

Scott Gifford sgifford at suspectclass.com
Fri Jan 18 01:37:17 GMT 2008


I ran into an interesting problem earlier today.  I have a Unix
machine I maintain in a largely Windows shop.  They use Windows Backup
for their backups, and so I created a readonly share of the entire
filesystem with one user, "backup", who is an admin user.  This lets
them back up the entire Unix machine by attaching to the "backup"
share, but nothing can be changed.  So far so good.

I'm backing up just essential files on the system, "/etc", "/home",
and "/usr/local".  We started running the backup, and it first
estimated 3GB, which is about right.  As it ran, though, it kept
increasing its estimate; we stopped it at about 20GB.  Closer
inspection showed that it was confused by circular links to

The default Apache configuration on our system has a circular link,
with "/etc/apache/conf" -> "/etc/apache".  I believe this is for
compatibility, since Apache configuration files used to be in
"/etc/apache/conf", but that's beside the point.  This is installed by
the OS, so I'm reluctant to remove it, since other packages could
depend on it being present.

The problem was that circular link.  Samba would resolve the symlink
for the client, and so the client would recurse into a directory it
was already in, and so just keep backing up forever.

I looked at disabling symlinks, but the docs said this will return
errors when they are read.  I suspect this would upset the backup

Does anybody have a suggestion for dealing with this?



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