From: Ian Soboroff <isoboroff@acm.org>
To: Max Waterman <davidmaxwaterman@fastmail.co.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: io performance...
Date: Wed, 25 Jan 2006 09:19:39 -0500 [thread overview]
Message-ID: <9cfek2wz8xw.fsf@rogue.ncsl.nist.gov> (raw)
In-Reply-To: <43D71C75.2050807@fastmail.co.uk> (Max Waterman's message of "Wed, 25 Jan 2006 14:36:37 +0800")
Max Waterman <davidmaxwaterman@fastmail.co.uk> writes:
>>> We're still wondering why rd performance is so low - seems to be the
>>> same as a single drive. RAID10 should be the same performance as RAID0
>>> over two drives, shouldn't it?
>>>
>> I think bonnie++ measures accesses to many small files (INN-like
>> simulation) and database accesses. These are random accesses, which
>> is the worst access pattern for RAID. Seek time in a RAID equals the
>> longest of all the drives in the RAID, rather than the average. So
>> bonnie++ is domninated by your seek time.
>
> You think so? I had assumed when bonnie++'s output said 'sequential
> access' that it was the opposite of random, for example (raid0 on 5
> drives) :
>
I could be wrong, I was just reading the information from the bonnie++
website...
Ian
next prev parent reply other threads:[~2006-01-25 14:19 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-16 7:35 io performance Max Waterman
2006-01-16 7:32 ` Jeff V. Merkey
2006-01-17 13:57 ` Jens Axboe
2006-01-17 19:17 ` Jeff V. Merkey
2006-01-16 8:35 ` Pekka Enberg
2006-01-17 17:06 ` Phillip Susi
2006-01-18 7:24 ` Max Waterman
2006-01-18 15:19 ` Phillip Susi
2006-01-20 5:58 ` Max Waterman
2006-01-20 13:42 ` Ian Soboroff
2006-01-25 6:36 ` Max Waterman
2006-01-25 14:19 ` Ian Soboroff [this message]
2006-01-25 13:09 ` Bernd Eckenfels
2006-01-18 3:02 ` Max Waterman
2006-01-18 4:30 ` Jeff V. Merkey
2006-01-18 5:09 ` Max Waterman
2006-01-18 4:37 ` Jeff V. Merkey
2006-01-18 7:06 ` Max Waterman
2006-01-18 9:21 ` Alan Cox
2006-01-18 15:48 ` Phillip Susi
2006-01-18 16:25 ` Bartlomiej Zolnierkiewicz
2006-01-19 0:48 ` Adrian Bunk
2006-01-19 13:18 ` Max Waterman
[not found] <5vx8f-1Al-21@gated-at.bofh.it>
[not found] ` <5wbRY-3cF-3@gated-at.bofh.it>
[not found] ` <5wdKh-5wF-15@gated-at.bofh.it>
2006-01-19 1:58 ` Robert Hancock
2006-01-19 13:14 ` Max Waterman
2006-01-19 14:08 ` Alan Cox
2006-01-20 4:09 ` Max Waterman
2006-01-20 4:27 ` Alexander Samad
2006-01-20 12:52 ` Alan Cox
2006-01-19 11:39 Al Boldi
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