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From Lee Parker <...@socialagency.com>
Subject Re: concurrent reads
Date Tue, 13 Jul 2010 14:25:46 GMT
The iostat numbers are rather low as is cpu utilization.  We have a couple
of nightly jobs which do a lot of reads in a short amount of time.  That is
when the pending reads was climbing.  I'm going to bump up the number and
see how things run.

Lee Parker
On Tue, Jul 13, 2010 at 6:18 AM, Schubert Zhang <zsongbo@gmail.com> wrote:

> For read, the bottleneck is usually the disk.
> Use iostat to check the utility of your disks.
>
>
>
>
> On Tue, Jul 13, 2010 at 2:07 PM, Peter Schuller <
> peter.schuller@infidyne.com> wrote:
>
>> > Has anyone experimented with different settings for concurrent reads?  I
>> > have set our servers to 4 ( 2 per processor core ).  I have noticed that
>> > occasionally, our pending reads will get backed up and our servers don't
>> > appear to be under too much load.  In fact, most of the load appears to
>> be
>> > from GC.  Is 3 per processor core too much?  Does it matter if it is an
>> AMC
>> > vs Intel processor?  How does processor clock speed or cache play into
>> this
>> > setting?
>>
>> Increase concurrency until you're able to either saturate CPU or
>> saturate the disk subsystem. Note that the more disks you have, the
>> more concurrency you'll need to fully utilize them.
>>
>> --
>> / Peter Schuller
>>
>
>

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