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To: martin hudec <corwin@aeternal.net>
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cc: freebsd-stable@freebsd.org
Subject: Re: Higher ATA-Mode -> lower speed
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martin hudec wrote:

>   amber# dd if=/dev/zero of=/usr/testfile bs=64k count=2000
>   131072000 bytes transferred in 2.546718 secs (51467023 bytes/sec)
>  
>
These are not very usefull tests of raw disk bandwith because they use 
the filesystem (and are hence subject to the vagiaries of block 
allocation, etc) and are not likely to be very repeatable or 
comparable.  Nore are the big enough or long enough to reduce the 
variance of the result or cover one-off spikes (e.g. what if it is 
running just when a cron job happens to kick off?)