Re: raid1 performance

Bernd Eckenfels (ecki-news2002-06@lina.inka.de)
Sat, 29 Jun 2002 02:01:00 +0200


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
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