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Date: Thu, 18 May 2006 14:02:19 +1200
From: Mark Kirkwood <markir@paradise.net.nz>
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To: Mike Jakubik <mikej@rogers.com>
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Cc: freebsd-stable@freebsd.org
Subject: Re: Sequantial IO Performance improvement in 6.1-STABLE
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Mike Jakubik wrote:
> Mark Kirkwood wrote:
>> Mark Kirkwood wrote:
>>> I recently upgraded my FreeBSD machines from 6.0R to 6.1-STABLE
>>>
>>> I noticed a pleasant surprise - improved disk IO!
>>>
>>> In 6.0R best sequential throughput I ever saw was 170 MB/s (32k block 
>>> size reads on an 4G file). In 6.1-STABLE I'm seeing 190 Mb/s (32k 
>>> block size reads on an 4G file).
>>>
>>
>> Would have been even better if I'd spelled "sequential" correctly in 
>> the subject :-(...
>>
>> I'm also seeing sequential write speed increasing from 120Mb/s to 
>> 140Mb/s.
>>
>> I did wonder if this increased IO throughput is what is triggering the 
>> posts about data corruption in 6.1 - i.e. more throughput means more 
>> heat to dissipate!
> 
> Or, maybe the file was in a different location on the disk. Outer and 
> inner tracks perform differently. Did you test with the same exact file 
> and the same file system?
> 

Good point, but yes - I made sure that a pre-existing file was used for 
the *read* test.

About the *write* test - I am mistaken unfortunately, as I found some 
old test results showing 137Mb/s, I conclude that 140Mb/s is not 
significantly different from that!

Cheers

Mark