Another thing that will cause backup of a file in either UNIX or WIndows
environment is if someone changes the Access Control list (permissions) on a
file or directory.

> ----------
> From:         Richard Sims[SMTP:rbs AT bu DOT edu]
> Sent:         Friday, July 17, 1998 9:17 AM
> To:   ADSM-L AT vm.marist DOT edu
> Subject:      Re: ADSM Incr Backup Criteria
>
> >I don't know exactly the criteria ADSM uses to determine whether to
> backup a
> >file or not...
>
> In the Unix environment, at least:
> ADSM examines the file's attributes such as size, modification date and
> time
> (mtime), ownership (UID), group (GID), and compares it to those attributes
> of the most recent backup version of that file.  (atime - access time - is
> ignored.)
>
> As an aside, note that things get "interesting" when users manage their
> HSM files.  For example, a user decides to change the group affiliation of
> all files in a directory containing old, large files, as in:
> 'chgrp -R SOMEGROUP .'.  The next incremental backup sees all these files
> as having been changed, and goes to back them up again.  Because they are
> old, their data is now on tape, which needs another tape drive and
> probably
> hours to perform the backup - all incited by this little, innocent
> command.
> Because ADSM is generic to numerous platforms, it operates by object name,
> and so does not remember that this inode is the same one it has always
> been,
> so as to simply update its datbase info rather than back up the whole
> object
> (file) again.
>
>    Richard Sims, Boston University OIT
>