From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 6 Mar 2008 07:40:02 +0100 From: Enrico Weigelt To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: Re: [9fans] thoughs about venti+fossil Message-ID: <20080306064002.GD18329@nibiru.local> References: <20080305055255.GA4575@nibiru.local> <7f575fa27b41329b9ae24f40e6e5a3cd@plan9.bell-labs.com> <20080306040441.GA18329@nibiru.local> <14ec7b180803052015k6957e809p7c58dfa03545e026@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <14ec7b180803052015k6957e809p7c58dfa03545e026@mail.gmail.com> User-Agent: Mutt/1.4.1i Topicbox-Message-UUID: 7045795e-ead3-11e9-9d60-3106f5b1d025 * andrey mirtchovski wrote: > i think what you fail to take into consideration is the fact, that > even if the chance of a collision may be relatively high by your > standards, the chance that the colliding blocks have data of any > significance is very, very low. Okay, valid point. For my personal things (eg. large media collections) this would be perfectly fine, since the data isn't that important and a few broken data blocks aren't that harmful (loosing an frame in an movie is even hard to notice). But for HA applications, we still need some additional redundancy or at least some error diagnostics at application level. Well, we'll most likely needs this anyways, eg. to detect human fault or code bugs. My current idea is to use two separate hash functions in parallel (as many sw distros already do). But I've got no idea if this really helps or collissions in SHA-1 will often go parallel with colissions in the second hash (eg. MD5). cu -- --------------------------------------------------------------------- Enrico Weigelt == metux IT service - http://www.metux.de/ --------------------------------------------------------------------- Please visit the OpenSource QM Taskforce: http://wiki.metux.de/public/OpenSource_QM_Taskforce Patches / Fixes for a lot dozens of packages in dozens of versions: http://patches.metux.de/ ---------------------------------------------------------------------