Re: Hardware advice - Mailing list pgsql-performance

From scott.marlowe
Subject Re: Hardware advice
Date
Msg-id Pine.LNX.4.33.0305301330060.31612-100000@css120.ihs.com
Whole thread Raw
In response to Re: Hardware advice  (Will LaShell <will@lashell.net>)
List pgsql-performance
On 30 May 2003, Will LaShell wrote:

> On Fri, 2003-05-30 at 07:44, Andrew Sullivan wrote:
> > On Fri, May 30, 2003 at 03:23:28PM +0100, Adam Witney wrote:
> > > RAID5 for 3x 146Gb drives
> >
> > I find the RAID5 on the PERC to be painfully slow.  It's _really_ bad
> > if you don't put WAL on its own drive.
>
> This seems to be an issue with the dell firmware.  The megaraid devel
> list has been tracking this issue on and off for some time now.  People
> have had good luck with a couple of different fixes. The PERC cards
> -can- be made not to suck and the LSI cards simply don't have the
> problem. ( Since they are effectively the same card its the opinion that
> its the firmware )

I've used the LSI/MegaRAID cards in the past.  They're not super fast, but
they're not slow either.  Very solid operation.  Sometimes the firmware
makes you feel like you're wearing handcuffs compared to the relative
freedom in the kernel sw drivers (i.e. you can force the kernel to take
back a failed drive, the megaraid just won't take it back until it's been
formatted, that kind of thing).

The LSI plain scsi cards in general are great cards, I got an UWSCSI card
by them with gigabit ethernet thrown in off ebay a couple years back and
it's VERY fast and stable.

Also, if you're getting cache memory on the megaraid/perc card, make sure
you get the battery backup module.


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