ADSM-L

Re: Performance problems

1997-09-16 17:03:43
Subject: Re: Performance problems
From: "Iseli,Dominique,VEVEY,FC-SIL/INF" <Dominique.Iseli AT NESTLE DOT COM>
Date: Tue, 16 Sep 1997 23:03:43 +0200
Did you check if you are using the same packet size on tcpip as before
and if the migration didn't change you this parameter ???
I a not an AIX specialist but on MVS I had similar perf problems and
using a very large packet size improves a lot the transfer.(Of course if
Routers switches and so support it)
Hope it's help.
Iseli Dominique.
>-----Original Message-----
>From:  Bryan Baars [SMTP:bbaars AT CASECORP DOT COM]
>Sent:  Tuesday, 16. September 1997 21:12
>To:    ADSM-L AT VM.MARIST DOT EDU
>Subject:       Performance problems
>
>We recently upgraded our RS/6000 box to AIX 4.2.  Prior to this upgrade,
>ADSM backups were taking anywhere from 1.5 to 2 hours to process.  Now,
>however, backups are taking 4.5 hours and even longer.  The amount of
>data being backed up is the same.  Here are some details about the
>server/upgrade:
>
>During the upgrade planning, IBM told us to install the following for
>ADSM and our Magstar tape drive:
>
>        Atape driver (for Magstar)      3.1.0.6
>        ADSM client                     2.1.0.6
>        ADSM Server                     2.1.5.13
>
>The server is a J40 with 4 CPUs.  There is one internal drive for
>rootvg.  This is where ADSM is installed, as well as the database,
>recovery log, and storage pool definitions.  This is the exact same
>configuration that we had prior to the upgrade (I realize storing the
>db, log, and stg. pools on the same disk will cause I/O contention - but
>we didn't experience these problems before...)
>
>In the ADSM backup logs, I see the data transfer rate vary anywhere from
>500KB/sec to 3,500KB/sec (yesterday's backup was around 3,500KB/sec, but
>the overall backup time took over 4 hours for 432MB total transfer with
>compression).  I would suspect some of the backups would take longer
>because I had a trace turned on, but even without the trace, the overall
>time was unbearable.  I have also noticed the system load average
>fluctuate between 1.00 and 15.00.  The CPU states also show very heavy
>kernel CPU usage, but then there can be 50% idle time.  iostat shows
>lots of small transfer rates while ADSM backs up small files (52KB -
>1000KB every 5 seconds) but more reasonable transfer rates (2MB-10MB
>every 5 seconds) while backing up larger files (20MB or bigger).  The
>ADSM trace files show a high time value in the Data Verb section, but I
>don't know what this means and whether or not this is normal.
>
>I have been working with ADSM support for two weeks now, and they
>haven't found any reasons why this is happening.  I've tweeked all the
>ADSM parms per their (IBM) recommendations.  In the last conversation I
>had with them, they wanted me to install the latest ADSM server patch
>2.1.5.15 and an OS bos patch that supposedly will help the process of
>ADSM writing to journaled filesystems.  I am leery of just throwing
>patches at my system - especially if IBM doesn't know if the patch will
>fix the problem.
>
>Has anyone experienced similar problems or does anyone have additional
>suggestions to help me troubleshoot this?  BTW - please respond directly
>to me (bbaars AT casecorp DOT com), I am still trying to get re-subscribed to
>this list.  Thanks in advance!
>--
>Bryan C. Baars                          CASE Corporation
>UNIX Administrator                      Racine, WI
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