Message-ID: <1117758630.429fa4a66825f@webmail.rawbw.com>
Date: Thu,  2 Jun 2005 17:30:30 -0700
From: mudfoot@rawbw.com
To: pgsql-performance@postgresql.org
Subject: Re: Adaptec/LSI/?? RAID (what about JBOD?)
References: <002601c56725$2bdd2010$0200a8c0@grownups>
	<DCBA6ED5-11AA-401F-90AF-AB3E23D9B61A@khera.org>
	<1117746123.429f73cb81fed@webmail.rawbw.com>
	<1117754368.10586.32.camel@lamb.mcmillan.net.nz>
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Thanks, Andrew.  I expect to choose between HBAs with no RAID functionality or
with the option to completely bypass RAID functionality--meaning that I'll
hopefully avoid the situation that you've described.  I'm mostly curious as to
whether the driver problems described for U320 Adaptec RAID controllers also
apply to the regular SCSI drivers.

Thanks.

Quoting Andrew McMillan <andrew@catalyst.net.nz>:

> On Thu, 2005-06-02 at 14:02 -0700, mudfoot@rawbw.com wrote:
> > I have a similar question about what to choose (either LSI or Adaptec
> U320), but
> > plan to use them just for JBOD drivers.  I expect to be using either net
> or
> > freebsd.  The system CPU will be Opteron.  My impression is that both the
> ahd
> > and mpt drivers (for U320 Adaptec and LSI, respectively) are quite stable,
> but
> > not from personal experience.  Like I said, I don't plan to have the cards
> doing
> > RAID in hardware.  Should I be pretty safe with either choice of HBA
> then?
> 
> On the machine I mentioned earlier in this thread we use the Megaraid
> for JBOD, but the card setup to use the disks that way was somewhat
> confusing, requiring us to configure logical drives that in fact matched
> the physical ones.  The card still wanted to write that information onto
> the disks, reducing the total disk space available by some amount, but
> also meaning that we were unable to migrate our system from a previous
> non-RAID card cleanly.
> 
> Regards,
> 					Andrew.
> 
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