From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jim Choate To: <9fans@cse.psu.edu> Subject: Re: [9fans] Observation about sharing network/grid In-Reply-To: <62b7f5143b97a535c09b7e42d86dfa80@caldo.demon.co.uk> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Date: Sun, 5 Oct 2003 17:03:39 -0500 Topicbox-Message-UUID: 60ab1294-eacc-11e9-9e20-41e7f4b1d025 On Sun, 5 Oct 2003, Charles Forsyth wrote: > still, you're right: NFS could have done that, and perhaps the suenix > re-implementations do. NFS has been doing that for at least two yeas on Solaris, HP/UX, and AIX. Might want to review the man pages. When I used to work for Tivoli we had to make sure this was turned off because of some low level sys call conflicts with Tivoli during installs from NFS images. Wasn't a big deal since most sites didn't see it as very usefull. In a public namespace/filesystem context however the importance changes dramatically. If you don't allow transitivity in the mounts (and lazy-update is another must have in the real world) then the source servers get completely bogged down. Just imagine trying to export the Gutenburg Project by forcing everyone to go to the project itself. By using this technology a handfull of sites around the country could make the primary connections and then export those out to their immediate region. Then as users hit the second level server, only files that have never been hit before (or have changed content even one bit) need be re-propogated. This whole 'a few sites share to another set of few sites' is the heart of 'small world networks'. It allows the network to scale without traffic growing with it, provided the number of connections per node is not too small or too large. Sort of like Goldilocks ;) -- -- God exists because mathematics is consistent, and the Devil exist because we can't prove it. Andre Weil, in H. Eves, Mathematical Circles Adieu ravage@ssz.com jchoate@open-forge.com www.ssz.com www.open-forge.com