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Date:      Wed, 5 Jul 2000 10:01:36 +0930
From:      Greg Lehey <grog@lemis.com>
To:        Linh Pham <lplist@q.closedsrc.org>
Cc:        JF Prieur <jfp51@ebeing.com>, freebsd-questions@FreeBSD.ORG
Subject:   Re: SMP performance of 4.0-Stable, RAID
Message-ID:  <20000705100135.G97425@wantadilla.lemis.com>
In-Reply-To: <Pine.BSF.4.21.0007041405210.4104-100000@q.closedsrc.org>
References:  <005001bfe5fb$00642ba0$ca0a000a@ackbar> <Pine.BSF.4.21.0007041405210.4104-100000@q.closedsrc.org>

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On Tuesday,  4 July 2000 at 14:10:55 -0700, Linh Pham wrote:
> On Tue, 4 Jul 2000, JF Prieur wrote:
>> Our webserver (dual P2/450, 256MB RAM, 4*9GB UltraWideSCSI) is currently
>> running IIS, ColdFusion and MySQL. We are in the process of weaning
>> ourselves off of NT and implementing FreeBSD wherever it is feasible.
>>
>> How is FreeBSD's SMP performance compared to NT. Also, since MySQL, for
>> example, runs about 40% faster on FreeBSd than NT, if BSD's SMP
>> performance is not up to par with NT, would it still be worth it to
>> migrate it to a uniprocessor FreeBSD box?
>>
>> Just trying to see where we can get rid of NT :-)
>>
>> Also, does FreeBSD do software RAID at all like NT or will I have to buy
>> a RAID card (I know that performance is better but we are on a very
>> tight budget)
>
> SMP performance under FreeBSD 4.0 has been improved a bit over FreeBSD
> 3.x.

I don't know of any changes which would have affected performance.

> I'm not sure if it's up to par with Windows 2000's or other
> commercial operating system's SMP performance though.

FreeBSD 4.0 still has somewhat simplistic SMP support.  In many cases
it's very good, but in others we have seen really poor performance.
About all we can say at the moment is "measure your own performance".
Microsoft 2000 does in fact have SMP support which is better than
FreeBSD's in some areas; I don't know whether that makes up for known
deficiencies in other areas, but I suspect it would normally not do so.

> FreeBSD has software RAID support through vinum (correct me if I'm
> wrong) which supports RAID 0 and 1 (possibly 0+1) but I don't know
> if it will do RAID 5 via software or not.

It's described in the man page.  Yes, Vinum includes support for
RAID-5.

> Hardware RAID controllers will usually have better performance over
> software RAID controllers (mostly with RAID 5) since the processor
> on the controller (if any) will handle the I/O processing, leaving
> your CPUs for other important tasks (like running a Quake
> server...hehe). Just remember that RAID 5 will increase read
> performance but will slaughter write performance ;)

Note also that the processors on the RAID controllers are much slower
than those on your motherboard, so it's not a foregone conclusion that
hardware RAID will perform better than software RAID.

Greg
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