Review of Experience with Grapevine (Schroeder et al)

From: Prasanna Kumar Jayapal (prasak_at_winse.microsoft.com)
Date: Mon Feb 02 2004 - 17:39:31 PST

  • Next message: Alexander G Balikov: "Review: Schroeder, et al. Experience with Grapevine: The Growth of a Distributed System"

    This paper ("Experience with Grapevine - The growth of distributed
    systems") describes an early distributed, replicated system, "Grapevine"
    and presents a report on what the authors have learnt from using this
    system in a large and practical environment. The authors also talk about
    the potential improvements that were not carried out, hoping that their
    experience may offer some help to designers of new systems.

    A Grapevine system is composed of a wide area network dotted with
    Grapevine servers, one or more of which is typically located (and
    services) within a given local area network. It mainly provides
    messaging and registration services. The registration data which
    controls the messaging activities is stored in the registration
    database. This database consists of entries (called RNames) and there
    are two types: group entries (contains set of info about groups and
    individuals like distribution lists, ACLs, etc) and individual entries
    (like passwords, inbox sites, etc). Replication of key data makes for a
    reliable, reconfigurable system.

    The authors discuss remarkably well the effect of a large number of
    users on the system and how small design decisions may turn to be system
    bottlenecks. One issue with a distributed system of this type is its
    scalability, which is given due attention in this paper. Among
    particularly interesting problems discussed are how and when to increase
    the number of servers, performance issues of distributing mails for long
    (and possibly nested) distribution lists, the increasing flow of mails
    among far away nodes (and how multistep forwarding improves efficiency
    and robustness under unreliable links), and the different
    tradeoffs between safety and higher communication bandwidth (or update
    delays) when control data (registries) are replicated. Nevertheless,
    many of the paper's suggestions are based on only quantitative empirical
    evidence, and hence, it is not clear whether some of the solutions can
    be extrapolated to other distributed systems.

    One interesting aspect of the paper is that it cleverly introduces
    solutions to several (currently standard) issues presented in both
    e-mail server configuration and network topology design (like mailing
    groups and recursive mail aliasing, distributed mail delivery,
    replication of services and space distribution organized under domain
    names - registry -).

    The success of the authors in achieving the goals of a distributed,
    reliable, performance-oriented meta system is best reflected in the
    comment: "most users and registrars treat Grapevine as if it were
    implemented on a single, large, reliable computer ... to which all
    workstations were connected through high-speed links."

    Unfortunately, it doesn't appear as though Grapevine will "become the
    source of authentication and access control information for the
    internet." This may partly be due to freezing the Grapevine design and
    implementation before its time. I wonder if they ever thought of a
    distributed Operating system at that time. Overall, I think this was a
    good paper to read through and understand the necessities of a
    distributed system.


  • Next message: Alexander G Balikov: "Review: Schroeder, et al. Experience with Grapevine: The Growth of a Distributed System"

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