Re: I/O wait question/scenario

on 2/24/2004 4:10 AM bordenm_at_methodisthealth.org said the following:
> Ok, here is the scenario. We have an application, clinical, that the
> db server is having pretty high I/O wait. It can be as high as 50 to
> 60%, but it is not consistently like this. It is more consistently
> around 30 to 40 during busy times. This is running on a p690 regatta
> attached to a shark. The partition is set up with 7procs and 16gig of
> ram. After the vendor has researched this a little, they have said the
> the I/O wait will go down once we add more users to the application.
> They are saying that the I/O wait is high because the processesors are
> so fast that it processes the transactions faster than what it can
> handle. Like I said, they say that the I/O wait will go down once we
> make the runqueues go up by adding more users to the application. To
> me, this doesn not sound correct.

Sounds to me like BS. It is like the doctor saying, cut your little finger and your migraine will go away.

What does your average IO latency look like from V$FILESTAT?

-V

> My question is, could this theory be correct? If it is correct,
> doesn't that mean that we have an I/O bottle neck period and it should
> be resolved? In my mind,since this application is on a SAN that we
> should have almost no I/O wait and maybe more run queues than anything
> period, no matter how many users are on the box.
>
> Thanks for you comments and opinions.
>
> Mike
Received on Tue Feb 24 2004 - 13:19:12 CST