From: Steve Poe <steve.poe@gmail.com>
To: Scott Marlowe <smarlowe@g2switchworks.com>
Cc: Jim C. Nasby <jnasby@pervasive.com>
Cc: Luke Lonergan <LLonergan@greenplum.com>
Cc: Alex Turner <armtuk@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgresql Performance on an HP DL385 and
Date: Wed, 9 Aug 2006 18:24:07 -0700
Message-ID: <721b21dc0608091824j684dc35do887da4e1fa58069@mail.gmail.com> (raw)
In-Reply-To: <1155159448.20252.121.camel@state.g2switchworks.com>
References: <3E37B936B592014B978C4415F90D662D03FFEF6E@MI8NYCMAIL06.Mi8.com>
<721b21dc0608082245u6ee62e7dg522ff18e4d72683@mail.gmail.com>
<20060809210539.GR40481@pervasive.com>
<721b21dc0608091411g3a1a6e60q449de0d91020f9dc@mail.gmail.com>
<1155159448.20252.121.camel@state.g2switchworks.com>
Scott,
Do you know how to activate the writeback on the RAID controller from HP?
Steve
On 8/9/06, Scott Marlowe <smarlowe@g2switchworks.com> wrote:
>
> On Wed, 2006-08-09 at 16:11, Steve Poe wrote:
> > Jim,
> >
> > I'll give it a try. However, I did not see anywhere in the BIOS
> > configuration of the 642 RAID adapter to enable writeback. It may have
> > been mislabled cache accelerator where you can give a percentage to
> > read/write. That aspect did not change the performance like the LSI
> > MegaRAID adapter does.
>
> Nope, that's not the same thing.
>
> Does your raid controller have batter backed cache, or plain or regular
> cache? write back is unsafe without battery backup.
>
> The default is write through (i.e. the card waits for the data to get
> written out before acking an fsync). In write back, the card's driver
> writes the data to the bb cache, then returns on an fsync while the
> cache gets written out at leisure. In the event of a loss of power, the
> cache is flushed on restart.
>
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To: pgsql-performance@postgresql.org
Cc: steve.poe@gmail.com, smarlowe@g2switchworks.com, jnasby@pervasive.com, LLonergan@greenplum.com, armtuk@gmail.com
Subject: Re: Postgresql Performance on an HP DL385 and
In-Reply-To: <721b21dc0608091824j684dc35do887da4e1fa58069@mail.gmail.com>
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