Date: Wed, 14 Mar 2001 15:19:30 -0700 (MST) From: Nate Williams <nate@yogotech.com> To: Dan Nelson <dnelson@emsphone.com> Cc: Dag-Erling Smorgrav <des@ofug.org>, freebsd-arch@FreeBSD.ORG, Nate Williams <nate@yogotech.com> Subject: Re: [PATCH] add a SITE MD5 command to ftpd Message-ID: <15023.61042.768406.854325@nomad.yogotech.com> In-Reply-To: <20010314161646.A1482@dan.emsphone.com> References: <20010314105918.A5204@roaming.cacheboy.net> <35525.984597779@critter> <20010314210758.A2405@roaming.cacheboy.net> <15023.53743.215996.538067@nomad.yogotech.com> <20010314130025.A3031@dragon.nuxi.com> <xzpelw0yqun.fsf@flood.ping.uio.no> <20010314161646.A1482@dan.emsphone.com>
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> > > The checker can *easily* keep a list of files sizes and date stamps > > > and compare that. > > > > Date stamps are useless. They'd be different on different master > > sites anyway. File size is almost as bad, as two files can very > > easily be totally different and still have the same size. > > But how often do port distfiles change, but keep their size? Often enough that it's been seen. > Pretty low, I'd say, at least compared to the number of times the size > changes and the filename stays the same. True, but now we'd have to modify every port to include both the MD5 *AND* filesize information in the port. Right now the MD5 is part of the port, so all the information is necessary in the ports tree to do the SITE-MD5, except for the ftp infrastructure. > Another thing to consider before adding SITE MD5 as a command is that > it's an extremely slow operation. md5'ing a 10MB file takes about > 1/3rd of a second on my pIII/600. It would take 5 minutes of CPU time > to md5 1-gig worth of sources, and that's assuming that the FTP server > is idle. ftpd would have to cache the md5 checksum somewhere for it > to be acceptable, and then you've got the same caching problem (how > does ftpd know when the file has changed to is can update its cached > md5?). Is that cost greater than the cost of sending the data out over the wire? Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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