From: EJ Vincent <ej@ejane.org>
Cc: linux-raid@vger.kernel.org
Subject: Re: Suboptimal raid6 linear read speed
Date: Wed, 16 Jan 2013 15:40:11 -0500 [thread overview]
Message-ID: <50F7102B.3030307@ejane.org> (raw)
In-Reply-To: <20130116160957.GB10165@kevin>
On 1/16/2013 11:09 AM, Charles Polisher wrote:
> keld@keldix.com wrote:
>> Hi Charles
>>
>> It really does not show below which layout you use for RAID10. This is quite
>> important as the different layouts of RAID10 have quite different
>> performance characteristics. The 'far' layout tends to be the fastest.
>> Which command did you use to create the RAID10 array?
>
>
> mdadm --create /dev/md1 --chunk=64 --level=10 \
> --raid-devices=8 --spare-devices=0 \
> --parity=n2 \
> /dev/sd[abcdefgh]1
>
>>> # cat /proc/mdstat
>>> Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath]
>>> md1 : active raid10 sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
>>> 2118656 blocks 64K chunks 2 near-copies [8/8] [UUUUUUUU]
> ^^^^^^^^^^^^^
> I will be testing far placement as well.
>
> I very much appreciate your interest and guidance. To clarify my
> goals, I am trying to demonstrate generalized RAID charac-
> teristics using an experimental workbench in various config-
> urations, tying the observed experimental data to expected
> values. I'd like to wring out obvious errors in my experimental
> technique.
>
> The initial motivation was a glaringly poor choice of RAID level
> for a performance-sensitive production system which I have to
> live with for years to come. The most unsettling aspect was that
> the selection process was stymied by the complexity of the
> choices and an abundance of disinformation. I want to address
> this pitfall by publishing an illustrated guide to performance,
> cost, and reliability up and down the storage stack, helping
> people to make reasoned choices in purchasing and configuring
> storage. Varying the RAID level and configuration are key (but
> not the only) parts of this work. I'm well along in the
> literature search, workbench setup, and toolchain. I'm expecting
> to put a year or two into the project and to open source
> everything.
>
> Best regards,
I am excited to see the results of this project. Good luck! I'll be
waiting patiently.
--
EJ Vincent
ej@ejane.org
next prev parent reply other threads:[~2013-01-16 20:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-15 12:33 Suboptimal raid6 linear read speed Peter Rabbitson
2013-01-15 12:45 ` Mikael Abrahamsson
2013-01-15 12:56 ` Peter Rabbitson
2013-01-15 16:13 ` Mikael Abrahamsson
2013-01-15 12:49 ` Phil Turmel
2013-01-15 12:55 ` Peter Rabbitson
2013-01-15 17:09 ` Charles Polisher
2013-01-15 19:57 ` keld
2013-01-16 4:43 ` Charles Polisher
2013-01-16 6:37 ` Tommy Apel Hansen
2013-01-16 9:36 ` keld
2013-01-16 16:09 ` Charles Polisher
2013-01-16 20:40 ` EJ Vincent [this message]
2013-01-15 23:17 ` Phil Turmel
2013-01-16 2:48 ` Stan Hoeppner
2013-01-16 2:58 ` Peter Rabbitson
2013-01-16 20:29 ` Stan Hoeppner
2013-01-16 21:20 ` Roy Sigurd Karlsbakk
2013-01-17 15:51 ` Mikael Abrahamsson
2013-01-18 8:31 ` Stan Hoeppner
2013-01-18 9:18 ` Mikael Abrahamsson
2013-01-18 22:56 ` Stan Hoeppner
2013-01-19 7:43 ` Mikael Abrahamsson
2013-01-19 22:48 ` Stan Hoeppner
2013-01-19 23:51 ` Maarten
2013-01-20 0:16 ` Chris Murphy
2013-01-20 0:49 ` Maarten
2013-01-20 1:37 ` Phil Turmel
2013-01-20 9:44 ` Chris Murphy
2013-01-20 6:26 ` Mikael Abrahamsson
2013-01-20 9:39 ` Chris Murphy
2013-01-20 16:55 ` Mikael Abrahamsson
2013-01-20 17:15 ` Chris Murphy
2013-01-20 17:17 ` Mikael Abrahamsson
2013-01-20 17:20 ` Chris Murphy
2013-01-19 23:53 ` Phil Turmel
2013-01-20 9:04 ` Wolfgang Denk
2013-01-20 19:28 ` Peter Grandi
2013-01-20 21:09 ` Mikael Abrahamsson
2013-01-20 21:50 ` Peter Grandi
2013-01-21 5:24 ` Mikael Abrahamsson
2013-01-21 14:40 ` Peter Rabbitson
2013-01-21 20:32 ` Peter Grandi
2013-01-21 20:55 ` Peter Grandi
2013-01-21 22:00 ` Peter Grandi
2013-01-19 13:21 ` Roy Sigurd Karlsbakk
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