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Date:      Fri, 09 Feb 2007 20:52:17 -0500
From:      Mike Andrews <mandrews@bit0.com>
To:        freebsd-stable@freebsd.org
Subject:   Re: What is a good choice of sata-ii raid controller for freebsd?
Message-ID:  <45CD2551.2070206@bit0.com>
In-Reply-To: <200702091441.39848.josh@tcbug.org>
References:  <00ad01c74b65$79db1710$0c00a8c0@Artem> <45CC72D4.9040104@lxnt.info>	<01e601c74c5d$31be19c0$0c00a8c0@Artem> <200702091441.39848.josh@tcbug.org>

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Josh Paetzel wrote:

> What hardware RAID buys you over gmirror is that you can boot from it.  
[snip]
> From a raw speed perspective on an unloaded CPU a 3.0ghz processor is 
> probably just as fast or faster than the embedded processor on a RAID 
> card running at a few hundred mhz.  Sure, once you start talking 
> about CPUs at full load there are advantages to off-loading stuff to 
> a dedicated processor.

What hardware RAID buys me over gmirror is that SATA2 NCQ actually works 
on recent hardware RAID cards, and doesn't on gmirror -- at least 
according to the ata(4) manpage on 6.2-RELEASE.  Depending on your 
specific application, that could have a performance impact, no?


-- 
Mike Andrews  *  mandrews@bit0.com  *  http://www.bit0.com
It's not news, it's Fark.com.                  Carpe cavy!



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