From: Jeff Breidenbach <breidenbach@gmail.com>
To: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Al Boldi <a1426z@gawab.com>, Gordon Henderson <gordon@drogon.net>,
linux-raid@vger.kernel.org
Subject: Re: Multiplexed RAID-1 mode
Date: Mon, 1 Aug 2005 02:09:20 -0400 [thread overview]
Message-ID: <e03b90ae050731230950444b63@mail.gmail.com> (raw)
In-Reply-To: <17133.41835.683675.621675@cse.unsw.edu.au>
Hi Neil,
Are you suggesting I do this?
mdadm --create /dev/md0 --level=10 --raid-devices=2 \
--parity=f2 /dev/sdc1 /dev/sdd1
I just tried it and it appears dog slow - for example
hdparm -t /dev/md0 claims 18MB/s, and I see a similar
number in /proc/mdstat for resync speed.
Getting rid of the --parity=f2 parameter, the numbers
jump up to about 65MB/s which is similar to single drive
transfer rate.
Anyway, I haven't thoroughly benchmarked and I know hdparm
is not to be trusted, but so far it's not obvious to me level=10
beats level=1 for a two drive array. If you think it is worth
pursuing I will do so.
Cheers,
Jeff
PS. I care most about small (~5K) file read performance. Think
very busy webserver with hundreds of gigabytes of small files.
And an occasional medium size file of a few megabytes.
next prev parent reply other threads:[~2005-08-01 6:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-31 5:04 SATA RAID-1 benchmarks Jeff Breidenbach
2005-07-31 9:31 ` Gordon Henderson
2005-07-31 16:06 ` Multiplexed RAID-1 mode Al Boldi
2005-08-01 4:22 ` Neil Brown
2005-08-01 6:09 ` Jeff Breidenbach [this message]
2005-08-01 6:23 ` Neil Brown
2005-08-01 14:12 ` Al Boldi
2005-07-31 11:58 ` [RAID] SATA RAID-1 benchmarks Julian Cowley
2005-07-31 18:36 ` Jeff Breidenbach
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