ADSM-L

Re: Memory Tuning For AIX

2002-01-02 16:05:29
Subject: Re: Memory Tuning For AIX
From: Miles Purdy <PURDYM AT FIPD.GC DOT CA>
Date: Wed, 2 Jan 2002 15:02:10 -0600
Hi Denis,

I think your using too much memory for file caching. Here's why:

a couple of things:
your box is out of 'real' memory, 'fre' column.
ignore 'r' and 'b', for now
any number in the pi and po columns are bad
The 'sr' search column is how many pages in the list where searched before 'fr' 
column number of pages where freed.
As the others said IO wait is a problem.

First tune 'vmtune'.
This is my command from my TSM server, AIX 4.3.3 on a silver node - which is 
H50.
/usr/samples/kernel/vmtune -f 256 -F 768 -u 32 -p 20 -P 70 -r 2 -R 64 -b 128 -l 
65536 -B 547 -w 32000

Set the lower and upper free pages, f and F, 256 and 768 are good
Experiment with p and P, but I would think P should be low for you. Try 70.
r and R should be 2 and 64

What are your disks? SCSI? SSA?
How much paging space do you have? 136237 pages of 'active virtual memory' is 
only 532 MB.

Be really careful when you try this I CRASHED BOX WHEN I DID THIS:
you can use vmtune -h to force 'P' to be a hard limit. Set this in rc.local.

Email me more info. I like these problems.

Miles

----------------------------------------------------------------------------------------------
-------------------
Miles Purdy 
Miles Purdy 
System Manager
Farm Income Programs Directorate
Winnipeg, MB, CA
purdym AT fipd.gc DOT ca
ph: (204) 984-1602 fax: (204) 983-7557

"If you hold a UNIX shell up to your ear, can you hear the C?"
-------------------------------------------------------------------------------------------------
----------------------
>>> dlhuillier AT PERSHING DOT COM 02-Jan-02 12:33:59 PM >>>
>>> dlhuillier AT PERSHING DOT COM 02-Jan-02 12:33:59 PM >>>
Hello-
I am having a memory problem.
I am runnning AIX 4.3.2 on a H50.  TSM is the only application
running on the server.  When I run vmstat I get the following...

kthr     memory             page              faults        cpu
----- ----------- ------------------------ ------------ -----------
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
 0  0 136233   202   0   3   2  99  210   0  52  240  66 17 30 16 37
 1  3 136234   342   0  38  11 3727 4204   0 1322 6136 4665 12 11  3 74
 2  3 136236   160   0  44  12 3728 5326   0 1324 5844 4644 10 11  2 76
 1  3 136237   295   0  17  19 4113 5725   0 1305 7174 5091 13 10  3 74
 0  3 136237   629   0  19   9 4240 7442   0 1316 7200 5082 14 13  5 68

Does this look normal to anyone?  From my limited understanding of vmstat
it looks like:
CPU utilization is maxed out
I have blocked processes (the b column)
The scan rate (sr) column is very high.
The server has 1Gig of memory.  I'm really not sure how to tell how much is
allocated to
the OS and how much is allocated to TSM.  Does anyone have any ideas or
pointers is
tuning memory for AIX?  Do I need a memory upgrade?
I started checking this because my server response is horrible.
Thanks.
Denis
<Prev in Thread] Current Thread [Next in Thread>