From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@cse.psu.edu Subject: Re: [9fans] venti In-Reply-To: Message from "rob pike" of "Wed, 30 Jan 2002 00:52:14 EST." <20020130055215.F326C19A0C@mail.cse.psu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <20214.1012371813@apnic.net> From: George Michaelson Date: Wed, 30 Jan 2002 16:23:33 +1000 Topicbox-Message-UUID: 49031724-eaca-11e9-9e20-41e7f4b1d025 > Of course, but the beauty of Venti is the ease with which it provides > the hooks you need to address such issues. Replication, mirroring, > load balancing, all those things are made trivial by the realization that > a hash is a universal address space. Except as the paper says, get above petabytes, and the *choice* of hash gets harder/slower because it has to be 'better'. ie, too universal makes the hash function less nice. I like the comments about certain operations on older data being extremely expensive. This resonated with my memories of using archival storage on the TOPS-10 system, where you stalled for Operators to find the tape, load the temporary pack, copy the tape to the pack, put that content into exposed filespace in a place you could find it, and get back to you. ICL CAFS might have been there, except it was the usual UK R&D 20+ years before viable market/technology. Oh, the joys of doing research to far ahead of the game... if they made the hash function for URI/URN compatible, passing around a referent in the web might wind up going back to the canonical data anyway. cheers -George