Re: Disk Benchmarking Question - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: Disk Benchmarking Question
Date
Msg-id CAOR=d=33jpYDj8vVKE_9r4gyfF76VH0H0vTOcf_GomR4aj_jyA@mail.gmail.com
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In response to Re: Disk Benchmarking Question  (Scott Marlowe <scott.marlowe@gmail.com>)
Responses Re: Disk Benchmarking Question
List pgsql-performance
On Sat, Mar 19, 2016 at 4:29 AM, Scott Marlowe <scott.marlowe@gmail.com> wrote:

> Given the size of your bonnie test set and the fact that you're using
> RAID-10, the cache should make little or no difference. The RAID
> controller may or may not interleave reads between all four drives.
> Some do, some don't. It looks to me like yours doesn't. I.e. when
> reading it's not reading all 4 disks at once, but just 2, 1 from each
> pair.

Point of clarification. It may be that if two processes are reading
the data set at once you'd get a sustained individual throughput that
matches what a single read can get.


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