APAR PQ50760 describes a looping condition with two migration processes and high
and low migration thresholds set to zero.  This condition occurred for TSM
V4.1.2 for OS/390 with two migration processes and high and low thresholds set
to 10 and 5 respectively.  In this condition, no commands are processed,
including HALT.  No other work is processed either.  Cancelling the server and
restarting it does not help because the migration processes are restarted
automatically and the loop is entered again.
I applied the local fix in APAR PQ50760 and was able to avoid restoring the TSM
database.  The fix is to start the server with the undocumented option
NOMIGRRECL which prevents migration on server startup.
___________________________________

William White
Mainframe Services Group
International Computing Centre (ICC)
e-mail: white AT unicc DOT org