From: Chris Snook <csnook@redhat.com>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
xfs@oss.sgi.com
Subject: Re: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++)
Date: Wed, 28 May 2008 11:40:24 -0400 [thread overview]
Message-ID: <483D7CE8.4000600@redhat.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0805280442330.4527@p34.internal.lan>
Justin Piszcz wrote:
> Hardware:
>
> 1. Utilized (6) 400 gigabyte sata hard drives.
> 2. Everything is on PCI-e (965 chipset & a 2port sata card)
>
> Used the following 'optimizations' for all tests.
>
> # Set read-ahead.
> echo "Setting read-ahead to 64 MiB for /dev/md3"
> blockdev --setra 65536 /dev/md3
>
> # Set stripe-cache_size for RAID5.
> echo "Setting stripe_cache_size to 16 MiB for /dev/md3"
> echo 16384 > /sys/block/md3/md/stripe_cache_size
>
> # Disable NCQ on all disks.
> echo "Disabling NCQ on all disks..."
> for i in $DISKS
> do
> echo "Disabling NCQ on $i"
> echo 1 > /sys/block/"$i"/device/queue_depth
> done
Given that one of the greatest benefits of NCQ/TCQ is with parity RAID,
I'd be fascinated to see how enabling NCQ changes your results. Of
course, you'd want to use a single SATA controller with a known good NCQ
implementation, and hard drives known to not do stupid things like
disable readahead when NCQ is enabled.
-- Chris
next prev parent reply other threads:[~2008-05-28 15:40 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-28 8:53 Performance Characteristics of All Linux RAIDs (mdadm/bonnie++) Justin Piszcz
2008-05-28 10:54 ` Peter Rabbitson
2008-05-28 11:05 ` Justin Piszcz
2008-05-28 15:40 ` Chris Snook [this message]
2008-05-28 17:32 ` Justin Piszcz
2008-05-28 17:53 ` Justin Piszcz
2008-05-28 19:22 ` Chris Snook
2008-05-28 19:27 ` Justin Piszcz
2008-05-29 9:57 ` Kasper Sandberg
2008-05-29 21:08 ` Justin Piszcz
2008-05-28 20:03 ` Richard Scobie
2008-05-28 20:01 ` Justin Piszcz
2008-05-28 16:34 ` Jens Bäckman
2008-05-28 16:40 ` Chris Snook
2008-05-28 16:46 ` Bryan Mesich
2008-05-28 17:33 ` Justin Piszcz
2008-05-28 18:57 ` Alan Cox
2008-05-28 23:00 ` Bill Davidsen
2008-05-29 11:22 ` Alan Cox
2008-05-30 12:22 ` Bill Davidsen
2008-05-28 19:02 ` Keld Jørn Simonsen
2008-05-28 19:05 ` Justin Piszcz
2008-05-28 23:09 ` Bill Davidsen
2008-05-29 6:37 ` Michal Soltys
2008-05-29 6:44 ` Holger Kiehl
2008-05-29 12:06 ` Justin Piszcz
2008-05-29 17:02 ` Justin Piszcz
2008-05-30 12:55 ` Bill Davidsen
2008-05-30 14:23 ` Keld Jørn Simonsen
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