Re: Who is causing the iowait?

From: tunla (lars.tunkrans_at_bredband.net)
Date: 06/28/05 

Date: 28 Jun 2005 14:01:02 -0700

Darren Dunham wrote:
> tunla <lars.tunkrans@bredband.net> wrote:
>
> > well in your case the most likely culprit is the the Kernel.
> > this is because your machine is starved for memory You are having
> > 1.2 GB data on swap and only 1 GB RAM. so most likely you system disk
> > is thrashed.
>
> It's an oracle database, and he's running solaris 8. that makes it
> really hard to tell if this is bad or not. However, I'd suspect that
> it's not a problem.
>
> If the system were thrashing, you'd get significant system time, not i/o
> wait.
>
> Remember i/o wait is *idle* time.

  Yes but, its because it cant do anything else than waiting.

  Maybe I am having bad dreams of old horrors.

   Let the OP report his usage of the system disk :

    iostat -x 10 10

  so we can see if its working at capacity . If it does
  ( and the oracle database is located on another drive )

  and

   sar -gp 10 10

   shows that huge amounts paging is taking place

  He will need more RAM.

   //Lars