From: Mike Rylander <mrylander@gmail.com>
To: Luke Lonergan <llonergan@greenplum.com>
Cc: PFC <lists@peufeu.com>
Cc: Jeffrey W. Baker <jwbaker@acm.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Huge Data sets, simple queries
Date: Wed, 1 Feb 2006 17:57:47 +0000
Message-ID: <b918cf3d0602010957n7d0ba9cetb290a0cda1b951d0@mail.gmail.com> (raw)
In-Reply-To: <C00632F4.1B71F%llonergan@greenplum.com>
References: <op.s4ad01lhcigqcu@apollo13>
<C00632F4.1B71F%llonergan@greenplum.com>
On 2/1/06, Luke Lonergan <llonergan@greenplum.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@gmail.com
GPLS -- PINES Development
Database Developer
http://open-ils.org
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To: pgsql-performance@postgresql.org
Cc: mrylander@gmail.com, llonergan@greenplum.com, lists@peufeu.com, jwbaker@acm.org
Subject: Re: Huge Data sets, simple queries
In-Reply-To: <b918cf3d0602010957n7d0ba9cetb290a0cda1b951d0@mail.gmail.com>
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