From: ahemavathy (ahemavathy_at_hotmail.com)
Date: Mon Feb 02 2004 - 10:20:46 PST
This paper concentrates more on the post system design problems faced then on the design of the system. The authors seem very sober, warning future designers about the various problems that they'll face. It was funny to read that they became sceptical about making changes to their system later, wondering what repercussions any new changes will cause to the old system.
The paper is about the system Grapevine which was the mail delivery, naming, authentication and access control system in Xerox. The system consists of the mail component and the registration component. The mail service takes care of mail delivery to clients while the registration service takes care of naming, authentication, access control and resource location.The information about users, machines, access control lists etc is stored in a registration database. This database is distributed and replicated. The client programs of Grapevine obtain its services through the Grapevine User package.
They concentrated on the scaling of the system by use of more servers of fixed power rather than by using more powerful servers.Also interesting is the fact that, each message servers expand distributions lists only one level and further steering list expansions are done by some grapevine server whose registration server would know that registry.Thus the load on a server is proportional to its registry size and not on the distribution list size. While their system defined registries based on geographical areas, they advise that registries based on organizations would be a better idea. Grapevine also served as authentication means to use a file server.They must have faced quite a few problems in implementing this system and keeping it running as they have designed a few tools such as the viticulturist's entrance for remote monitoring and some logging tools.
I found this paper a bit tough to read as I don't have much knowledge on the working of mail servers. But while reading I could relate to some of the problems in the system that are visible to the users such as duplicate messages, late delivery and some distribution lists problems. All in all it was an enlightening paper for me.
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