Skip site navigation (1) Skip section navigation (2)

Re: Perc 3 DC

From: Steve Clark <sclark(at)netwolves(dot)com>
To: glynastill(at)yahoo(dot)co(dot)uk
Cc: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Perc 3 DC
Date: 2008-11-24 13:23:54
Message-ID: 492AAAEA.9030106@netwolves.com (view raw or flat)
Thread:
Lists: pgsql-performance
Glyn Astill wrote:
> --- On Sat, 22/11/08, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)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.

In response to

Responses

pgsql-performance by date

Next:From: tvDate: 2008-11-24 13:39:24
Subject: Re: Hash join on int takes 8..114 seconds
Previous:From: AndrusDate: 2008-11-24 12:35:25
Subject: Re: Hash join on int takes 8..114 seconds

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group