RE: RAID1 & 2.6.9 performance problem

["J. Ryan Earl" <ryan@dynaconnections.com>]

I missed that, sounds like you got an IDE concurrency problem.  Perhaps you
can't read from both ports for some reason.  Don't think it's a raid problem
though.

-ryan

-----Original Message-----
From: Janusz Zamecki [mailto:janusz@pipi.ma.cx]
Sent: Tuesday, January 18, 2005 12:41 PM
To: J. Ryan Earl
Cc: linux-raid@vger.kernel.org
Subject: RE: RAID1 & 2.6.9 performance problem


W liście z wto, 18-01-2005, godz. 18:34, J. Ryan Earl pisze:
> "You will get 2 parallel sequential reads at around 120MB/sec
> assuming you're not bus limited."
>
> To clarify because this looks ambiguous to me now, you should be able to
> perform 2 parallel sequential reads both at 60MB/sec = 120MB/sec total.
>
> -ryan
>

Hi,

Unfortunatelly it is not the case. Please go to my original e-mail. I've
ran two simultaneous tests and I get:


hdparm -t /dev/md6 &
hdparm -t /dev/md6

This is the result:

--disk/hdg----disk/hde-
_read write _read write
    0     0 :   0     0
    0     0 :   0     0
  124k    0 :26.0M    0
  368k    0 :45.5M    0
    0     0 :   0     0
    0     0 : 896k    0
  124k    0 :1568k    0
    0     0 :   0     0

One disk works with 75% of its full speed, the second one works with
0,6% of its full speed or even less.

Best regards, Janusz

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