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Date:      Mon, 13 Aug 2001 08:05:39 -0700
From:      "Kevin Oberman" <oberman@es.net>
To:        "Kevin Hui - DCS" <khui@cs.toronto.edu>
Cc:        "Alfred Perlstein" <bright@mu.org>, freebsd-questions@FreeBSD.ORG
Subject:   Re: Experiencing very slow raw write speeds on /dev/ad1 
Message-ID:  <200108131505.f7DF5dR30168@ptavv.es.net>
In-Reply-To: Your message of "Sun, 12 Aug 2001 23:02:27 EDT." <003401c123a4$63e5d560$07010101@mtwx1.on.home.com> 

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> From: "Kevin Hui - DCS" <khui@cs.toronto.edu>
> Date: 	Sun, 12 Aug 2001 23:02:27 -0400
> 
> Correct me if I'm wrong, but I do not think that turning (1) and (2) on
> would matter in this case since they are both for file-system-level
> performance tuning.  I am access the raw device here, bypassing the
> file-system layer.

Right you are! I'm afraid I missed that obvious detail.

In your case I believe enabling write cache is about all that can be
done.

I wonder if the lack of "raw" disk partitions on FreeBSD might be an
issue here. (Yes, the raw devices are still there, but there is no
longer any difference between them and the "cooked" devices.) This is
a bit beyond my expertise.

R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman@es.net			Phone: +1 510 486-8634

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