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From: Sandy Rutherford <sandy@krvarr.bc.ca>
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Date: Tue, 21 Jun 2005 18:15:51 -0700
To: Alex Zbyslaw <xfb52@dial.pipex.com>
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Cc: freebsd-questions@freebsd.org, Ted Mittelstaedt <tedm@toybox.placo.com>
Subject: Re: Yet another RAID Question (YARQ)
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>>>>> On Mon, 20 Jun 2005 11:36:32 +0100, 
>>>>> Alex Zbyslaw <xfb52@dial.pipex.com> said:

 > Ted Mittelstaedt wrote:
 >>> Sandy
 >>> Rutherford
 >>> Sent: Sunday, June 19, 2005 10:52 PM
 >>> 
 >>> 
 >>> In order to boost read performance, a RAID card should interleave
 >>> reading from a RAID-1 volume by reading alternately from one drive and
 >>> then the other.  You can see this in alternate blinking of the
 >>> activity lights of the drives.  If you are not seeing this when
 >>> copying a large file, then this would suggest that a RAID-1 volume is
 >>> not working as it should.
 >>> 
 >>> 
 >>> 
 >> 
 >> Incorrect.  What you are describing is RAID-0.  RAID-1 is mirroring.
 >> Here's
 >> 
 >> 
 > I don't think you read the message correctly.  It said that *reads* were 
 > interleaved not that the *data* was interleaved.

That's exactly what I said.  Thanks.

Ted, I am aware that RAID 1 is mirroring.  However, any proper
implementation of RAID 1 should also boost read performance and if
during a read you are not seeing activity on both drives in the RAID 1
volume, then I would say this is a good indication that something is
wrong.

Sandy