From owner-freebsd-hackers  Wed Oct 27 17: 2: 5 1999
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From: Don Lewis <Don.Lewis@tsc.tdk.com>
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Date: Wed, 27 Oct 1999 17:00:43 -0700
In-Reply-To: Julian Elischer <julian@whistle.com>
       "Re: why FFS is THAT slower than EXT2 ?" (Oct 27,  2:51pm)
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To: Julian Elischer <julian@whistle.com>,
	Mike Smith <mike@smith.net.au>
Subject: Re: why FFS is THAT slower than EXT2 ?
Cc: Ilia Chipitsine <ilia@cgilh.chel.su>,
	David Scheidt <dscheidt@enteract.com>,
	Chuck Robey <chuckr@picnic.mat.net>, Ben Rosengart <ben@skunk.org>,
	Chuck Youse <cyouse@paradox.nexuslabs.com>, questions@FreeBSD.ORG,
	hackers@FreeBSD.ORG
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On Oct 27,  2:51pm, Julian Elischer wrote:
} Subject: Re: why FFS is THAT slower than EXT2 ?
} 
} 
} On Wed, 27 Oct 1999, Mike Smith wrote:
} 
} > > in order to save space I gzip'ped output of my tests. 
} > > ungzipping ports tarball on FreeBSD took 28 min
} > > on Linux --- about 2.5 times faster.
} > 
} > This is something we already know, and it's not the sort of test that 
} > you should ever headline as "why is FFS so much slower"?
} 
} Kirk has said that it would be possible for the FFS to modify its
} behaviour if it notices this usage pattern.

The basic problem is that the directory layout policy that FFS uses
is very non-optimal in this case.  This was discussed extensively
on freebsd-hackers last year, search the list archive for
	Reading/writing /usr/ports VERY slow

Carl Mascott noticed nearly a 3x speedup when he untarred /usr/ports
on FFS filesystem that was generated with only one cylinder group.


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