| From: | Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> |
|---|---|
| To: | Dave Stibrany <dstibrany(at)gmail(dot)com> |
| Cc: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Disk Benchmarking Question |
| Date: | 2016-03-19 10:32:13 |
| Message-ID: | CAOR=d=33jpYDj8vVKE_9r4gyfF76VH0H0vTOcf_GomR4aj_jyA@mail.gmail.com |
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| Lists: | pgsql-performance |
On Sat, Mar 19, 2016 at 4:29 AM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)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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