From: Steve Clark <sclark@netwolves.com>
To: glynastill@yahoo.co.uk
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Perc 3 DC
Date: Mon, 24 Nov 2008 08:23:54 -0500
Message-ID: <492AAAEA.9030106@netwolves.com> (raw)
In-Reply-To: <707711.35257.qm@web23603.mail.ird.yahoo.com>
References: <707711.35257.qm@web23603.mail.ird.yahoo.com>
Glyn Astill wrote:
> --- On Sat, 22/11/08, Scott Marlowe <scott.marlowe@gmail.com> wrote:
>
>
>>You really have two choices. First is to try and use it as
>>a plain
>>SCSI card, maybe with caching turned on, and do the raid in
>>software.
>>Second is to cut it into pieces and make jewelry out of it.
>
>
> Haha, I'm not really into jewelry, although I had thought of smacking it into a pile of dust with a lump hammer, that's much more my thing.
>
>
>> Anything
>>before the Perc 6 series is seriously brain damaged, and
>>the Perc6
>>brings the dell raid array line squarly in line with a 5
>>year old LSI
>>megaraid, give or take. And that's being generous.
>>
>
>
> Well this card thinks it's a 5 year old lsi megaraid. I've got a pile of perc5i megaraid paperweights on my desk at work, so this was kinda expected really.
>
>
>>>I've tried writeback and write through modes,
>>
>>tried changing cache flush times, disabled and enabled
>>multiple PCI delayed transactions, all seem to have little
>>effect.
>>
>>Yeah, it's like trying to performance tune a yugo.
>>
>
>
> Did I mention I drive a yugo?
>
>
>>>Finally I decided to wave goodbye to Dell's
>>
>>firmware. LSI has it down as a MegaRAID 493 elite 1600, so I
>>flashed it with their latest firmware. Doesn't seem to
>>have helped either though.
>>
>>Does it have a battery backup module? Often you can't
>>really turn on
>>write-back without one. That would certainly slow things
>>down. But
>>you should certainly expect > 20 M/s on a modern RAID
>>controller
>>writing out to a 4 disk RAID10
>>
>
>
> Yeah the battery's on it, that and the 128Mb is really the only reason I thought I'd give it a whirl.
>
>
>
>
Is the battery functioning? We found that the unit had to be on and charged before write back caching
would work.
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To: pgsql-performance@postgresql.org
Cc: sclark@netwolves.com, glynastill@yahoo.co.uk, scott.marlowe@gmail.com
Subject: Re: Perc 3 DC
In-Reply-To: <492AAAEA.9030106@netwolves.com>
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