Re: swapping

  • From: Jeremiah Wilton <jeremiah@xxxxxxxxxxx>
  • To: "Chen, Sarah" <Sarah_Chen@xxxxxxxxx>
  • Date: Thu, 6 Jan 2005 10:39:21 -0800 (PST)

On Thu, 6 Jan 2005, Chen, Sarah wrote:

> I am encountering high swapping problem on Oracle database with 16G
> RAM on Sun Sol 2.8 platform.
> Can anyone provide good UNIX commands/tips? I would also like to know how to
> find how much swap space for each running process?

A good place to start would be to find out which processes are using
the most resident memory, and thus forcing swapping.

On Solaris 8, you can run 'top -o res' to have top sort by resident

It could be one or just a few processes sucking up memory, or many
processes.  So also try 'ps -eo pid,rss,comm | sort -n +1' to display
all processes and their resident set size.

You have to do the math.  Add up all the resident memory being used by
processes and see how that compares available memory and swap space.
The sum of all frequently active processes has to fit into available
memory if you want to avoid swapping.

You can have many inactive processes occupying swap space with little
impact, so the math doesn't have to be perfect.

Jeremiah Wilton
ORA-600 Consulting
Emergencies - Seminars - Hiring

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