Yes; you would see an increased number of disk accesses at the os level,
both I and O, with significant level 2 overflow. This would also affect
locks; if I set a lock, the longer it takes me to find it, process it, and
write it back, the longer the lock is held. If it takes me a few dozen reads
to get the whole group, that can be a very significant delay. But if a high
percentage of the file is even just barely into level 2, that doubles the
i/o latency.
So you may be on to something there, but if that (resizing) doesn't do it,
the variables are legion.
I can tell you that I've worked with Tim Snyder in the past, and would not
hesitate to call on him again in the future if the need arises.
"Our greatest duty in this life is to help others. And please, if you can't
help them, could you at least not hurt them?" - H.H. the Dalai Lama
"When buying & selling are controlled by legislation, the first thing to be
bought & sold are the legislators" - P.J. O'Rourke
Dan Fitzgerald
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:owner-u2-
> [EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
> Sent: Wednesday, June 07, 2006 15:07
> To: u2-users@listserver.u2ug.org
> Subject: [U2] UniData performance problems
>
> We have had ongoing intermittent performance issues with InfoLease for
> many
> months now. Recently the problems have become worse, especially at
> monthend. Users and customers are complaining and we're out of ideas.
I'm
> hoping someone can point us in a direction that will get us to the root
> cause. I won't go into all the details, but here is some information on
> what we're seeing and what we've done.
>
> Application: InfoLease
> O/S: AIX 5.2.0.0
> DB version: UniData 6.0.8
> Disk: EMC
> HW: IBM P670 with two LPARs. One for production, the second cloned
nightly
> for reporting.
>
> * Both online and batch processing/reporting have taken a dive at
various
> times. Isssues used to be primarily a day or two before and after
> monthend,
> but we're creeping farther into the month as time goes on.
> * Slowness only affects InfoLease activity. Shell activity seems
> unaffected.
> * EMC (disk) tells us we are nowhere near taxing their system and
> read/write response times are in the 5-8 ms range
> * At the same time EMC says we're fine, AIX (filemon) indicate
significant
> read/write waits
> * Nmon regularly indicates a high number of CPU waits, but I've never
been
> able to map that back to user experience
> * When we experience slowdowns we may/may not be able to pinpoint a
> process
> or group of processes causing the problem.
>
> * Resizing seems to have pretty much resolved our batch processing but
> hasn't helped online activity. Udtmon still shows a surprising amount
over
> Overflow 2 activity. We're investigating, so maybe we have more work to
do
> there. Does anyone know what a system in overflow 2 looks like to the
O/S?
> Maybe a higher number of reads?
>
> It seems as if there is a bottleneck that noone can identify. Aside from
> periodic AIX read/write waits nothing shows any problems.
>
> TIA
>
> Brad Schrag
> InfoLease Development
>
>
>
--------------------------------------------------------------------------
> ----
> Electronic Privacy Notice. This e-mail, and any attachments, contains
> information that is, or may be, covered by electronic communications
> privacy laws, and is also confidential and proprietary in nature. If you
> are not the intended recipient, please be advised that you are legally
> prohibited from retaining, using, copying, distributing, or otherwise
> disclosing this information in any manner. Instead, please reply to the
> sender that you have received this communication in error, and then
> immediately delete it. Thank you in advance for your cooperation.
>
==========================================================================
> ====
> -------
> u2-users mailing list
> u2-users@listserver.u2ug.org
> To unsubscribe please visit http://listserver.u2ug.org/
-------
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe please visit http://listserver.u2ug.org/
-------
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe please visit http://listserver.u2ug.org/
