From: rick@snowhite.cis.uoguelph.ca
Date: 05/22/98-12:45:10 PM Z
From: rick@snowhite.cis.uoguelph.ca Date: Fri, 22 May 1998 13:45:10 -0400 (EDT) Message-Id: <199805221745.NAA11993@snowhite.cis.uoguelph.ca> Subject: backwards compatibity, etc Well, here's my $0.01 worth... I think that V4 should try and address some new ground, but should not try and solve all the world's distributed file system problems. (My sentiments are along the lines of what Dave said, which was a good post imho.) A few random thoughts: - As Dave mentioned, the major stumbling block for replication is the file handle, so I think serious thought should be put to alternative ways to identify a file (this also addresses the issue of location independence, or at least looks at it). At this point, I would lean towards a longhand identifier (such as a URL), with a short hand form similar to a file handle, but I haven't really thought this through. - If the file system is going to perform well over long haul nets, it must get away from the fine grained interaction typical of NFS RPCs. I really think that this comes down to some server state, such as "host A has attributes for file X cached", so that the client can afford to do long term caching without repeatedly going "are file X's attributes still YYY?". What I'm talking about here is along the lines of a server -> client callback system for updating client information, based upon server state. (I know, "NFS is stateless and that keeps recovery simple", but at some point this has to be questioned again.) - I'll go one step farther and suggest that V4 should be a protocol designed to work on top of TCP only. My argument for this is that you can easily tie server state to a TCP connection and server state recover is done whenever a TCP connection is re-established after it is broken, so the state recovery dilemma falls out pretty easily. I don't see an argument for using UDP any longer since NFS over TCP is now well enough understood and performs as well as UDP in most cases. It might be interesting for the group to look at the log of an old email list that Dr. Jeff Mogul had going a long time ago on state recovery and similar issues for NFS. Anyhow, keep the disscussion going, rick
This archive was generated by hypermail 2.1.2 : 03/04/05-01:45:45 AM Z CST