When local becomes global: an application study of data consistency in a networked world
Erik Riedel, Susan Spence and Alistair Veitch
Abstract:
As users and companies depend increasingly on shared, networked
information services, and as companies and customers become more
international, computer systems will need to keep pace with a global
scale. We believe that we will continue to see growth in large data
centers and service providers as new information services arise and
existing services are consolidated on one hand (for ease of
management, outsourcing, and reduced duplication), and further
distributed on the other hand (for fault-tolerance of critical
services and to accommodate the global reach of companies and
customers). This paper looks at storage systems in such a networked,
global environment, studies the characteristics of applications
demands on the storage system and quantifies how these demands might
be supported in such an environment. Our study focusses on a
collection of traces from several large commercial workloads taken on
single, centralized servers, and explores the inherent consistency and
performance requirements if these same applications were moved into a
networked, distributed setting. Rather than focussing on applications
or services "designed for the Web", we look at applications designed
to operate on local storage and examine how well or poorly they would
fare if they were migrated to a distributed setting. Our results
indicate that in many cases, the "inherent" level of consistency
required and the "true" amount of sharing is sufficiently low that
distribution may be feasible with reasonable performance, and without
wholesale application changes.
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Last modified: Tue Jul 10 21:36:53 PDT 2001 by Alistair Veitch (aveitch@hpl.hp.com)