From: Keld Simonsen <keld@keldix.com>
To: Marco <jjletho67-diar@yahoo.it>
Cc: Neil Brown <nfbrown@novell.com>, linux-raid@vger.kernel.org
Subject: Re: raid1 performance
Date: Sat, 31 Jul 2010 18:04:44 +0200 [thread overview]
Message-ID: <20100731160444.GA19780@rap.rap.dk> (raw)
In-Reply-To: <13942.81514.qm@web28516.mail.ukl.yahoo.com>
On Sat, Jul 31, 2010 at 03:21:40PM +0000, Marco wrote:
> >> sda 84.02
> >> sdb 113,69
> >> md2 8,01
> >>
> >> md2 and his meber have a very different ratio....
> >
> >Strange isn't it. And the ratios are the other-way-around to what I get.
> >I don't currently understand why ... but it might not be at all relevant to
> >the speed difference.
>
> Hi,
> i did some test on a different machine with centos 5.5 and ICH10 disk
> controller. On this machine i have no performance issue: hdparm -t return the
> same value (about 107 MB/s) on both /dev/md0 and its members
>
> I measured the "ratio" and i obtained 8.02 for md0 and 505 for meber disk. I it
> seems that the "raito" is not so relevant for this issue. What do you think ?
> In this case the md device was not mounted.
> I also tried several different io scheduler whithout noting any effect on
> sequential read eprformance.
>
> Marco
maybe try out raid10,f2 instead of raid1. You should get about double
the sequential read performance out of your raids, then, eg tested
with hdparm.
best regards
keld
next prev parent reply other threads:[~2010-07-31 16:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-25 14:58 raid1 performance Marco
2010-07-25 15:19 ` Roman Mamedov
2010-07-26 9:37 ` Marco
2010-07-26 10:24 ` Keld Simonsen
2010-07-26 10:53 ` John Robinson
2010-07-26 11:30 ` Keld Simonsen
2010-07-27 16:10 ` Marco
2010-07-26 11:03 ` Neil Brown
2010-07-27 1:23 ` Leslie Rhorer
2010-07-27 16:10 ` Marco
2010-07-27 22:23 ` Neil Brown
2010-07-28 12:10 ` Marco
2010-07-28 12:24 ` Neil Brown
2010-07-31 15:21 ` Marco
2010-07-31 16:04 ` Keld Simonsen [this message]
-- strict thread matches above, loose matches on Subject: below --
2010-07-19 12:14 Marco
2004-04-21 5:57 RAID1: Performance Mike Mestnik
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