ADSM-L

Again about performance and a lot of small files.

2001-08-07 11:50:08
Subject: Again about performance and a lot of small files.
From: Yury Us <us AT SOFTCOMPUTER DOT COM>
Date: Tue, 7 Aug 2001 11:49:42 -0400
Hi,
I have a problem with performance. It works extremely slow on few volumes.

Few words about environment:
AIX 4.3; TSM 4.1.3; IBM ULTRIUM library with 2 drives.

Library is splitted on two logical parts and the first half is used for
primary pool and second part for copy pool. The primary pool has collocation
on, but second no. Three nodes have a lot of small files.

Usually reclamation on volumes where is placed one of those nodes takes few
days, and that is unacceptable.
I made a search over the database and found few recommendations like use
reclamation using (1)"Reclaim Storage Pool" on disk or (2)move data to other
storage pool and let them migrate back. 

I was surprised that in (1) case data was not moved on Reclaim storage pool
with one shoot and them reclaimed during migration back. It started
reclamation during copying data on disk. Well I tried to move data on the
disk storage pool. Guess what happened? The system moves data file by file
(what is equal to reclamation). During those operations I checked activities
on disks and usage of the processor, but there was nothing. Looks like tape
drive used all the time. For 1G information it took 2hours.

The other problem is on collocated storage pool in most cases reclamation
starts without changing a status of volume. So when volume has the "filling"
status and reclamation goes very long(few days) the new information keep
adding to the same volume and it is endless.

If somebody can propose the other way around I would gladly appreciate it.

Thank you in advance.


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