Thanks for the reply.

If I don't set the LOWMIG=100, then when the storage pool hits 100%,
won't it start a migration process that will continue until it hits the
LOWMIG value?

My thought was that if I set both to 100, then a migration would not
take place ever.  I would then depend on my secondary pool to accept any
unexpected "excess data".  (which shouldn't occur, since we size our
primary storage pools (disk) to handle all data, but occasionally we get
an unexpected influx that we want to overflow to tape temporarily until
it can be "looked at").

Thanks again.

Eric Thompson
Senior Storage Engineer
www.it-lifeline.com

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Colin Dawson
Sent: Wednesday, April 15, 2009 10:07 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] High Mig Pct & Low Mig Pct = 100%

Howdy,

      We've seen many cases where folks set HIGHMIG=100.  I can't say
that
I've seen much where LOWMIG=100 is set or used in this fashion though...
Generally, HIGHMIG=100 is all that is needed to prevent migration from
trying to migrate the data from a given storage pool.

     The decision to overflow to the NEXT pool is done at the time that
the
server is trying to reserve space in a given pool.  If there is not
sufficient space available to reserve based on the incoming store
request,
it is at that point that the server will traverse to the NEXT pool and
attempt reservation/allocation in that pool.  The reservation and
allocation processing in this regard is pretty well independent of the
HIGHMIG setting for the storage pool.

-----------------------------------------------------
Colin Dawson
TSM Server Development
colind AT us.ibm DOT com


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  |04/15/2009 09:55 AM
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  |[ADSM-L] High Mig Pct & Low Mig Pct = 100%
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I want to keep all data on the primary storage pool (disk), yet allow
for overflows to the secondary pool (tape) in the event more data is
backed up than expected.



Has anyone ever set both High & Low Mig Pct = 100% ?



If I do this, will the data still overflow to the secondary storage pool
during a backup if the primary storage pool is full (100%)?  Or will I
get the "out of storage space" message.



Thanks.  Eric