From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 28 Apr 2003 18:13:01 -0400 From: William Josephson To: 9fans@cse.psu.edu Subject: Re: [9fans] fossil/venti/manber Message-ID: <20030428221301.GA17124@mero.morphisms.net> References: <69a4c6b7395b8751d482ae47469aed19@plan9.bell-labs.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <69a4c6b7395b8751d482ae47469aed19@plan9.bell-labs.com> User-Agent: Mutt/1.4.1i Topicbox-Message-UUID: 9a72acae-eacb-11e9-9e20-41e7f4b1d025 On Mon, Apr 28, 2003 at 05:55:34PM -0400, Russ Cox wrote: > I think the notes happen to answer your questions, mainly > because I think they clear up your misunderstandings about > how applying Manber's idea would actually work. > If you have questions after reading the notes, I'd be happy > to address them directly, but I think we're not on the same > page at the moment. For what it is worth, on common datasets (e.g. /usr and /home on Linux and FreeBSD boxes, the root disk on Windows boxes, and sets containing a majority of CAD and graphics files), using chunking turns out to be a significant win compared to fixed size blocks, at least over time. For the first run (i.e. first write of a set of files) and for small files, the difference is usually fairly trivial. The chunking approach is not as big a win as using content-addressed blocks in the first place, but still a win. Whether or not it makes sense to go to the effort of implementing it for Plan 9 is another question, of course. I'm afraid I can't name numbers as I'd like to do, but suffice it to say that this idea is being pursued commercially....