ADSM-L

Re: (U)Symbolic links in archives?

1998-09-10 04:28:21
Subject: Re: (U)Symbolic links in archives?
From: "S.F.Westbroek" <S.F.Westbroek AT H-W DOT NL>
Date: Thu, 10 Sep 1998 10:28:21 +0200
Brian D Chase wrote:
>
> On Fri, 4 Sep 1998, Monte Ambrose wrote:
>
> > We are looking into re-doing the way ADSM handles symbolic links.  I
> > agree that it definitely needs changes.  Currently we are looking into
> > making ADSM consistent with the way it backs up symbolic links for
> > Archive and Backup.  One possible solution: Followsymbolic=yes will not
> > follow the link for both.  Followsymbolic=no will not follow the link
> > for both.  We do not like to add to many options but perhaps Archive and
> > Backup should have their own option for Followsymbolic.  Does anyone
> > have input into how this might affect them?  Currently if we follow a
> > link and it results in a looping situation we detect it and we end the
> > loop.  If you have a situation where you are getting into a loop because
> > of this then you should pursue through technical support because it is a
> > bug.
>
> I'd be most happy with Followsymbolic=yes having the behavior of following
> all symbolic links through to completion except in cases where a loop is
> detected.   And then with Followsymbolic=no, it would be nice if it'd
> archive the symbolic link as such and be able to retrieve it as a symbolic
> link.  At least coming from a predominantly Unix background, those types
> of behavior make the most sense to me.
>
> As the client is currently implemented, there definitely appears to be
> some buggy behavior.  The looped links I've happened across consistently
> result in the archive process running until either the scratch media is
> exhausted, or until the ever growing path names of the files associated
> with the link exceed some limit in the path name length. I'll put together
> some test cases and try them out with the latest clients for the Unix
> systems we have.
>
> -brian.


This is a known problem and I agree it should be reported and fixed. To
create a workaround (I can't remember the exact implementation) a
programmer in a previous project of my created a C program which looks
for symbolic links and based on a given parameter removed it before
starting the backup/archive. But before removing it, the symbolic link
is registered and saved in a log. Running the program with another
parameter restored all symbolic links that have been removed.

This way you keep track of all symbolic links and don't run into loops
etc.


--
Met vriendelijke groeten/ With kind regards,
Met vriendelijke groeten/ With kind regards,
Simon Westbroek,
H&W IT Services, tel.+31(35)525 8892
S.F.Westbroek AT h-w DOT nl