RE: Performance Issues on 570

When you migrated, did you do anything to the files like reorganize
them?  Should you?  Do the files have a lot of deleted records?

I'm assuming that IBM has looked into reorganizing by access path or
making new access paths...  Were any libraries left out of the move?
Perhaps the old box had an access path in another library that was
actually helping you?

Did any of the file's definition change between old and new?  Do a DSPFD
on both boxes and look for differences.

Do you still have the old box so that you can run some benchmarks?  You
might want to run in debug on both boxes to see what access paths are
being used.  I'd also be curious to know the difference in CPU seconds
between the 2 boxes.

Did you do any application upgrades / conversions that may have
rearranged the records in the files?  Have you turned on REUSEDLT?  Is
this green screen or client/server/odbc?  Have you done anything with
triggers or referential constraints that might be new?

Journaling?  Mirroring?  If journaling, are the receivers in their own
ASP?  Receivers are essentially sequential writes, so it's nice if
they're in their on ASP so they don't cause contention with other
updates.

Have you added any access paths to the physical files involved?  More
access paths means slower updates...

How were the logical files created on the new box - through a restore or
through some compile process?  Compiling in the 'wrong' order can cause
more access paths to be maintained by the system.  Restoring them will
typically cause the box to decide that LOGICALA can piggyback on
LOGICALB, etc, causing the system to have to maintain fewer access
paths.

Good luck.
 
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-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Nelson Smith
Sent: Thursday, August 11, 2005 8:46 PM
To: Midrange Systems Technical Discussion
Subject: Re: Performance Issues on 570

About a month ago, my company upgraded from an 870 to a 570.  We went 
from 48G to 96G and more than doubled our disk capacity and increased 
the number of arms from around 90 to 128. We went down in processors 
from 12 to 11. Unfortunately, we also upgraded from V5R2 to V5R3 at the 
same time (I know, I know). 

After spending many hundreds of thousands of dollars, the sad result is 
that some of our major batch processes have more than doubled in run 
times.  For example, a 4-hour nightly billing run is now taking upwards 
of 9 hours.  Needless to say, there is much knashing of teeth going on 
around here and it is not a pleasant experience. It seems to be 
primarily a batch problem.  Processor efficiency and interactive 
response times seem to be improved.  During the batch runs, there seems 
to be a great amount of paging going on.

Both the old system and the new one, have (had) a development partitian 
and a production partition. Relative sizes have not changed.  There have

been no significant changes in database sizes or the applications. Both 
Business Partner and IBM have had many engineers working on the problem 
for a month now and of course, everyone is pointing fingers at everyone 
else.  They have been running every sort of performance management tool 
you can think of. They have tuned this and that. They have replace card 
after card.  They have tried all sorts of caching schemes.  All to no 
avail.

Lately, they are starting to point fingers at the applications.  Now I 
grant you that our applications are old and could stand much 
improvement, but they have not changed since before the upgrade.  We are

embarking on a modernation project in development, but we will not 
implement any such improvements until the upgrade issues are settled.

The one question I have not been able to get a straight answer out of 
any of these engineers, and the reason for this post, is what has been 
the experience of other recent converts to the 570?  Or, what has been 
the experience of other upgraders from V5R2 to V5R3? Particularly in 
relation to long-running batch jobs.  I can't think of anything unique 
in what we are running.  We have very little, if any, embedded SQL.  
That's the only thing I've seen any complaints about on this list.  Has 
anyone else going to a 570 experienced any sort of major slowdown?  At 
this point, we are willing to look at anything.