From: Ming Zhang <mingz@ele.uri.edu>
To: Mirko Benz <mirko.benz@web.de>
Cc: Neil Brown <neilb@cse.unsw.edu.au>,
Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: RAID 5 write performance advice
Date: Fri, 26 Aug 2005 10:30:21 -0400 [thread overview]
Message-ID: <1125066621.5549.27.camel@localhost.localdomain> (raw)
In-Reply-To: <430ECA18.10405@web.de>
i would like to suggest u to do a 4+1 raid5 configuration and see what
happen.
Ming
On Fri, 2005-08-26 at 09:51 +0200, Mirko Benz wrote:
> Hello,
>
> We have created a RAID 0 for the same environment:
> Personalities : [raid0] [raid5]
> md0 : active raid0 sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
> 1250326528 blocks 64k chunks
>
> *** dd TEST ***
>
> time dd if=/dev/zero of=/dev/md0 bs=1M
> 14967373824 bytes transferred in 32,060497 seconds (466847843 bytes/sec)
>
> iostat 5 output:
> avg-cpu: %user %nice %sys %iowait %idle
> 0,00 0,00 89,60 9,50 0,90
>
> Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
> hda 0,00 0,00 0,00 0 0
> sda 0,00 0,00 0,00 0 0
> sdb 455,31 0,00 116559,52 0 581632
> sdc 455,51 0,00 116540,28 0 581536
> sdd 450,10 0,00 116545,09 0 581560
> sde 454,11 0,00 116559,52 0 581632
> sdf 452,30 0,00 116559,52 0 581632
> sdg 454,71 0,00 116553,11 0 581600
> sdh 453,31 0,00 116533,87 0 581504
> sdi 453,91 0,00 116556,31 0 581616
> sdj 0,00 0,00 0,00 0 0
> sdk 0,00 0,00 0,00 0 0
> sdl 0,00 0,00 0,00 0 0
> sdm 0,00 0,00 0,00 0 0
> sdn 0,00 0,00 0,00 0 0
> md0 116556,11 0,00 932448,90 0 4652920
>
> Comments: 466 MB / 8 = 58,25 MB/s which is about the same as a dd to a
> single disk (58,5 MB/s). So the controller + I/O subsystem is not the
> bottleneck.
>
> Regards,
> Mirko
>
next prev parent reply other threads:[~2005-08-26 14:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-24 8:24 RAID 5 write performance advice Mirko Benz
2005-08-24 12:46 ` Ming Zhang
2005-08-24 13:43 ` Mirko Benz
2005-08-24 13:49 ` Ming Zhang
2005-08-24 21:32 ` Neil Brown
2005-08-25 16:38 ` Mirko Benz
2005-08-25 16:54 ` Ming Zhang
2005-08-26 7:51 ` Mirko Benz
2005-08-26 14:26 ` Ming Zhang
2005-08-26 14:30 ` Ming Zhang [this message]
2005-08-26 15:29 ` Mirko Benz
2005-08-26 17:05 ` Ming Zhang
2005-08-28 23:28 ` Neil Brown
2005-09-01 19:44 ` djani22
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