Re: Performance problems
1997-09-16 17:03:43
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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