| From: | Mike Rylander <mrylander(at)gmail(dot)com> |
|---|---|
| To: | Luke Lonergan <llonergan(at)greenplum(dot)com> |
| Cc: | PFC <lists(at)peufeu(dot)com>, "Jeffrey W(dot) Baker" <jwbaker(at)acm(dot)org>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Huge Data sets, simple queries |
| Date: | 2006-02-01 17:57:47 |
| Message-ID: | b918cf3d0602010957n7d0ba9cetb290a0cda1b951d0@mail.gmail.com |
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| Lists: | pgsql-performance |
On 2/1/06, Luke Lonergan <llonergan(at)greenplum(dot)com> wrote:
[snip]
> This is actually interesting overall - I think what this might be showing is
> that the Linux SW RAID1 is alternating I/Os to the mirror disks from
> different processes (LWP or HWP both maybe?), but not within one process.
I can confirm this behavior after looking at my multipathed fibre
channel SAN. To the best of my knowledge, the multipathing code uses
the same underlying I/O code as the Linux SW RAID logic.
--
Mike Rylander
mrylander(at)gmail(dot)com
GPLS -- PINES Development
Database Developer
http://open-ils.org
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