Well, Pct Migr is telling you how much of the data in the disk pool IS
migrate-able.
TSM can't migrate half of something, or a file that is incomplete.
So when your big DB backup is running, I suspect what TSM is telling you
is that only part of it has gotten to the disk pool yet.
As soon as the DB backup is complete in the disk pool, probably ALL the
data becomes migrateable and migration kicks in.
If you are having this problem, the best solution is usually to send the
big thing direct to tape.
After all, what is the point of sending it to the disk pool, if as soon
as it gets to the disk pool migration kicks in anyway?
You are just doing twice the I/O for n additional benefit.
And if the DB bakcup is the biggest thing in the disk pool, it will be
the first thing to migrate out!
Just set the Max Size Threshold on your disk pool to XXX GB, where XXX
is less than the size of your DB backup.
TSM will just bypass the diskpool for that Db backup and send it direct
to tape.
Results are the same, but it won't hurt as much.
Wanda Prather
"I/O, I/O, It's all about I/O" -(me)
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Andrew Carlson
Sent: Friday, August 05, 2005 2:05 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: High and Low Migration Percentage
I am wondering why TSM goes by Pct Migr rather than Pct Util to decide
when to migrate the storage pool. We are fairly disk constrained right
now. A couple of times a week, large database is backed up, that keeps
Pct Migr and Pct Util far apart. The storage pool fills up, but
migration
has not kicked in because Pct Migr is 30% to 40% lower than Pct Util. I
could adjust my levels, but it doesn't make sense for TSM to let the
storage pool fill up. Thanks.
--
Andy Carlson - Senior Technical Specialist
BJC Healtcare
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