From: Bill Davidsen <davidsen@tmr.com>
To: Mark Hahn <hahn@physics.mcmaster.ca>
Cc: Dexter Filmore <Dexter.Filmore@gmx.de>,
Linux RAID Mailing List <linux-raid@vger.kernel.org>,
Neil Brown <neilb@suse.de>
Subject: Re: 4 disks in raid 5: 33MB/s read performance?
Date: Wed, 24 May 2006 16:11:15 -0400 [thread overview]
Message-ID: <4474BDE3.7030905@tmr.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0605221231560.20391-100000@coffee.psychology.mcmaster.ca>
Mark Hahn wrote:
>>I just dd'ed a 700MB iso to /dev/null, dd returned 33MB/s.
>>Isn't that a little slow?
>>
>>
>
>what bs parameter did you give to dd? it should be at least 3*chunk
>(probably 3*64k if you used defaults.)
>
I would expect readahead to make this unproductive. Mind you, I didn't
say it is, but I can't see why not. There was a problem with data going
through stripe cache when it didn't need to, but I thought that was fixed.
Neil? Am I an optimist?
--
bill davidsen <davidsen@tmr.com>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
next prev parent reply other threads:[~2006-05-24 20:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-22 15:46 4 disks in raid 5: 33MB/s read performance? Dexter Filmore
2006-05-22 16:33 ` Mark Hahn
2006-05-24 20:11 ` Bill Davidsen [this message]
2006-05-25 4:56 ` Neil Brown
2006-05-22 23:02 ` Neil Brown
2006-05-24 8:21 ` Max. md array size under 32-bit i368 Gordon Henderson
2006-05-24 16:55 ` Ming Zhang
2006-05-25 4:54 ` Neil Brown
2006-06-06 9:36 ` Quick Question Gordon Henderson
2006-05-25 13:58 ` 4 disks in raid 5: 33MB/s read performance? Dexter Filmore
[not found] ` <44721F84.6060503@redhat.com>
2006-05-23 1:04 ` Dexter Filmore
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4474BDE3.7030905@tmr.com \
--to=davidsen@tmr.com \
--cc=Dexter.Filmore@gmx.de \
--cc=hahn@physics.mcmaster.ca \
--cc=linux-raid@vger.kernel.org \
--cc=neilb@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.