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Diagnosing vmstat output

Hi,

My vmstat output shows a lot of pageouts and the de is consistently more than 100.

This is a sure memory bottleneck.

How do I sort out the problem?What action and steps are to be taken immediately?

Regards,

karthikeyan

Nisus091197

Hi again,

Perhaps you could reduce the number of dataservers. Another thing you can do is to kill off any unnecessary processes.

Adding more memory will help, but it is important to understand why the memory is being used up. Is there a memory leak?

Regards, Nisus
http://www.omnimodo.com

schrodingers_cat

PAGEOUTS ARE NORMAL!!!! :-)

From a vmstat output, loads of stuff is misleading and can lead to the erronous conclusions.

Personally - if there was a single metric that is most useful - it would be memory scanrate. When you start to see high numbers here - it means that the page scanner is working hard to free up pages for other processes (e.g. a memory shortfall).

The scanrate is the 12th field (represented by SR).

karthik_selamel

ASKER

Hi Nisus,

Can you name which dataservers to reduce?And how to I identify unnecessary (I mean database related)processes?

I don't want to end up killing genuine processes and make a mess of things.

Regards,

Karthik

besky

OK, Nisus, if you know what you are talking about, go ahead.
Otherwise I would advise you to take another approach to the problem.

First question, version of Solaris, version of kernelpatch
Second, a processlist to determine what applications are running.
Third a ps -e -opid,vss,rss,args
Then a /usr/proc/bin/pmap -x PID to see the complete memoryusage of application processes.

It might be possible to use priority_pageing, or adjusting the desfree, minfree or scanrate params.
BUT CHECK THE SYSTEM FIRST, all applications are different.

It could be a shortage of shm which could be seen with ipcs.

Not trying to be a wise guy here but lets not have the guy shooting down his server if its not neccessary.

So, karthik, can you privide a little more info on the system ?

prtconf ---> gives total memory
sar -k 1 1 ----> gives kernel memory
vmstat 3 for free mem, scanrate and swaping ( pageing )

Have you got the Memtool application, prtmem is useful

ps -ef ---> gives all processes

A lot, I know, but performance konfiguration is a somewhat lenghty process. Like a car, you dont start with adding nitro to the fuel, teher are some other things to tune first.

HTH

karthik_selamel

ASKER

Hi Besky,

Thanks a lot for your elaborate briefing.Let me come back to you later.

Regards,

karthik

besky

Sure, but I guess the moderator would appriciate if you close aswered questions.

BTW, if you have money, there is a good book
Prentice Hall, Sun Blueprints series, Resource Management ISBN 0-13-025855-5
that covers most of the tuning stuff.

Nisus091197

karthikeyan,

Is this the DB server you have asked about in other questions?

karthik_selamel

ASKER

Hi,

No.

Karthik

Nisus091197

Hi,

If this is still a problem please give us more information. For example, using 'top' hit 'o' then 's' and paste in the results here.

Also show us the results of 'ps -efl'

and: /usr/platform/sun4u/sbin/prtdiag -v

Cheers.

Netminder

tfewster

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