I would image it does that because when the backup is first started, it
needs to split your fileset into two. At that point, it isn't aware of what
compression will do.  Now, once started, the different splits may compress
differently.  One might compress more than the other.

We have this happen all the time.  What is really annoying is when it asks
for another tape, you mount it, then the backup ends.  It might have used
about an inch of that tape. :)

-------------------------------------------------------------
Gary L. Paveza, Jr.
Technical Support Specialist

        -----Original Message-----
        From:   [log in to unmask] [SMTP:[log in to unmask]]
        Sent:   Wednesday, April 05, 2000 11:52 AM
        To:     [log in to unmask]
        Subject:        Parallel Backup using HP Store

        Currently we are using 2 DDS2 tape drives with compression on to
        perform our backups. A complete backup is about 13 gb of data. We
are
        currently using the sequential method and the only problem we have
is
        the amount of time it takes to do the backup. We started to
experiment
        with the parallel method and tested partial backups which performed
at
        about two-thirds the time of an identical sequential backup. When we
        perform a complete backup using the parallel method the backup gets
to
        about 95% completion and then asks for a third tape. Does anyone
have
        any ideas why we would need the extra tape?


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