I have a problem that comes up from time to time that I was wondering if
anyone else has experienced the same thing during disk to tape storage pool
migrations.  My ADSM environment is as follows:

ADSM MVS Server V2.1.10 running on OS/390 V1R2.
TCPIP for MVS V3.2
Client is HP-UX V10 running V2.1.6 of the ADSM Client
80GB disk storage pool migrated to Magstar 3590's in an STK Silo daily by
setting hi and lo thresholds to zero.
Disk pool migration thresholds are set at hi=95 lo=75 during the night.

The scenario is our disk pool fills up during the nightly backups and
migration begins.  Last night we got as high as 99.2% utilized while
migrations were running.  The problem, aside from having a disk pool that
is currently undersized, is that some client backup sessions show a status
of mediaw indefinitely.  I can understand that occurring initially when the
disk pool is 99+% full.  I mean hey there's no place for the data to go
right?   The problem is that even when the pool utilization drops to say
under 60% the sessions that showed mediaw still are stuck/not running still
showing a status of mediaw even though there appears to be plenty of space
available in the disk pool.  Does anyone know why these sessions are
hanging in a mediaw state and don't just start running as space becomes
available as data migrates from disk to tape?  I thought of setting the
high migration value to a lower number like 80 for example thinking that if
migration started before we reached such a high utilization factor  it
might avoid the apparent "gridlock".  Even if that fixes the problem it
still doesn't explain why the sessions hang in mediaw state indefinitely
and have to be eventually canceled even though space does become available
as data is migrated.  Any ideas?

Jeff Connor
Niagara Mohawk Power
Syracuse, NY