Re: Perc 3 DC

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От Steve Clark
Тема Re: Perc 3 DC
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Msg-id 492AAAEA.9030106@netwolves.com
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Ответ на Re: Perc 3 DC  (Glyn Astill <glynastill@yahoo.co.uk>)
Ответы Re: Perc 3 DC  (Glyn Astill <glynastill@yahoo.co.uk>)
Список pgsql-performance
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'smuch 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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