Oliver,

        You could turn caching off for the pool to insure space is
available.  Other options would include limiting the file size in the pool
(forcing the migration pool to receive the oversized files) or, as you
appear to be doing, migrate the pool to an empty state before backups are
done (set high and low thresholds to zero).  You may want to do the forced
migration before your backup window(s) start instead of after they complete.

        The best results will be achieved by setting the storage pool for no
cached copies.  This may delay restores by having to mount and search a tape
(if that is your primary migration pool) but it beats not doing a backup.

        Gary L. Ison
        Governor's Office for Technology
        101 Cold Harbor Drive
        Frankfort, Ky.   40601
        Phone:  (502) 564-8724
            Fax:  (502) 564-6856
E-mail: Gary.Ison AT mail.state.ky DOT us <mailto:Gary.Ison AT mail.state.ky 
DOT us>