Re: advice on memory configuration

From: Mark D Powell <Mark.Powell2_at_hp.com>
Date: Thu, 10 Nov 2011 05:44:52 -0800 (PST)
Message-ID: <803265ff-742e-425e-99d2-72d952af3b66_at_i4g2000prd.googlegroups.com>

On Nov 10, 5:28 am, vsevolod afanassiev
<vsevolod.afanass..._at_gmail.com> wrote:
> In Prod Buffer Cache Advisor doesn't work, it reports rubish.
> It Performance Test it worked and I included results in my post:
>
> >>Buffer Cache Advisory predicts improvement
> >>in performance for bigger cache: if cache is increased from 85 GB to
> >>170 GB number of physical reads should fall from 188 million to 85
> >> million.
>
> What I am looking for is advice on how to aproach this issue, what
> should we look at.
>
> Thanks

I would the starting point would be exactly what you have. The fact that you saw no real performance improvement when you bumped the buffer pool from around 50G to 80G should be taken at face value. In every system there is a point where the returns from more resources start to decline. In fact there is a point where adding another resouce especially cpu actually results in a decline in overall performance. These points depend on the application activity pattern and the manner in which the applicaiton is coded.

HTH -- Mark D Powell -- Received on Thu Nov 10 2011 - 07:44:52 CST