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Date: Wed, 06 May 2009 09:59:46 -0700
From: Benjamin Krueger <benjamin@seattlefenix.net>
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To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
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Cc: freebsd-performance@freebsd.org, Olivier Mueller <om-lists-bsd@omx.ch>,
	Bill Moran <wmoran@potentialtech.com>, freebsd-questions@freebsd.org
Subject: Re: filesystem: 12h to delete 32GB of data
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Wojciech Puchar wrote:
>> means you had 6 million files.  df -i would have been more useful in
> 
> 
>> the output above.
>>
>> This brings a number of questions up:
>> * Are you _sure_ softupdates is enabled on that partition?  That's
> 
> he showed mount output - he has softdeps on.
> 
>> * Are these 7200RPM disks or 15,000?  Again, going to make a big
>>  difference.
> 
> on 7200 RPM ordinary SATA disk i deleted 15 million files taking 300GB 
> (squid cache) in less than 30 minutes.
> 
> for sure it's because of his "hardware raid".
> 
> i've NEVER seen "hardware raid" that is actually faster than non-raid 
> config, or gmirror/gstripe config.
> 
> usually it's far much slower

Sorry, but my experience with that very server using a P400 controller 
with 256MB write cache is very different. My benchmarks showed that 
controller using Raid5 (with only 4 disks) is significantly faster than 
software layouts.

The days when hardware controllers could automatically be considered 
slow are long gone. The hardware does get faster over time. Don't make 
any assumptions without doing benchmarks.