The Snowflake Distributed System

We describe an emerging problem in globally distributed operating systems: the conflict between user requirements and administrative requirements. Then we describe the key to the solution: user-level resource aggregation. Next we outline the requirements of such a solution, and then we describe our specific implementation of the solution, which we call Snowflake. Finally, we discuss the metrics we will use to evaluate the Snowflake solution, and how to construct an experiment and measure the system to accomplish that evaluation. 1 The problem: a conflict between ease of use and ease of administration In times past, an operating system was defined as “hardware abstraction and resource management” [SS94a, Tan87]. That is, in some sense, a single-computer operating system was at the junction of users’ and administrators’ experience. Protection provided a mechanism for administration, and abstraction provided ease of use. Administrators were arbiters between users; the conflict was between users. As operating systems grew into distributed systems (local-area clusters), the challenge was finding suitable abstractions that harnessed larger systems into an easy-to-use environment. The conflict was between users and the unruly resources they were trying to find and use. As we enter a world in which more and more resources participate in a global network, a conflict is forming between users and administrators. The many users to one administrator relationship is generalizing into a many-to-many relationship. Because a single administrator no longer has total responsibility for a user’s experience, the emerging conflict is between ease of use (of separately administered resources) and ease of administration (of widely used resources). 1.1 What is ease of use? A user’s experience is greatly eased when resources are presented to him on his own terms. It is not enough that he can name any resource in the world; he should be able to give that resource a name that he finds mnemonic. Personal computers have exemplified this trend toward customizability; the general concept is that a user should see any resource in the world as part of his personal