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From: Bernd Eckenfels <ecki-news2002-06@lina.inka.de>
To: linux-kernel@vger.kernel.org
Subject: Re: raid1 performance
Date: Sat, 29 Jun 2002 02:01:00 +0200	[thread overview]
Message-ID: <E17O5fg-0004wl-00@sites.inka.de> (raw)
In-Reply-To: <20020502183758.Q31556@unthought.net>

In article <20020502183758.Q31556@unthought.net> you wrote:
>> No, you just distribute the ready round robin, this means each disk has only
>> half the seeks it had before. 

> No, this is the way it was done a long time ago.

> It turns out to be an incredibly bad idea.  In fact, it is the most CPU-efficient
> way of guaranteeing the largest average seek times on your disks  ;)

> The RAID-1 code now looks at which disk worked closest to the wanted position
> last, and picks that disk for the seek.

Thats right, it is done on the distance in sector numbers. Thats a simple
compare, not sure if one could do that better.

raid1.c:raid1_read_balance()

Greetings
Bernd

      reply	other threads:[~2002-06-28 23:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-04-30 12:23 raid1 performance Jaime Medrano
2002-04-30 12:38 ` Arjan van de Ven
2002-04-30 14:21   ` Kent Borg
2002-05-01 16:35     ` Jakob Østergaard
2002-05-01 17:01       ` Kent Borg
2002-05-01 17:16         ` Justin Cormack
2002-05-01 21:23         ` Bernd Eckenfels
2002-05-02 16:37           ` Jakob Østergaard
2002-06-29  0:01             ` Bernd Eckenfels [this message]

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