Re: I/O wait question/scenario

bordenm_at_methodisthealth.org wrote:

> 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.
>
> 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

Get them to put it in writing with a money back guarantee including $100/hour for any time wasted if it is not true.

With vendors NEVER NEVER NEVER EVER take what they say verbally on anything involving purchases without putting it in writing and making them sign it.

Even when they are right you should protect yourself.

-- 
Daniel Morgan
http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
damorgan_at_x.washington.edu
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