This chapter seeks to help an SA [system administrator] decide how much centralization is
appropriate, for a particular site or service, and how to transition between
more and less centralization.
Centralization means having one focus of control. One might have two
DNS servers in every department of a company, but they all might be controlled
by a single entity. Alternatively, decentralized systems distribute control
to many parts. In our DNS example, each of those departments might
maintain and control its own DNS server, being responsible for maintaining
the skill set to stay on top of the technology as it changes, to architect
the systems as it sees fit, and to monitor the service. Centralization refers
to nontechnical control also. Companies can structure IT in a centralized or
decentralized manner.
Centralization is an attempt to improve efficiency by taking advantage
of potential economies of scale: improving the average; it may also improve
reliability by minimizing opportunities for error. Decentralization is an attempt
to improve speed and flexibility by reorganizing to increase local
control and execution of a service: improving the best case. Neither is always
better, and neither is always possible in the purest sense. When each
is done well, it can also realize the benefits of the other: odd paradox,
isn't it?
Decentralization means breaking away from the prevailing hegemony,
revolting against the frustrating bureaucratic ways of old. Traditionally, it
means someone has become so frustrated with a centralized service that "do
it yourself" has the potential of being better. In the modern environment
decentralization is often a deliberate response to the faster pace of business
and to customer expectations of increased autonomy.
Centralization means pulling groups together to create order and enforce
process. It is cooperation for the greater good. It is a leveling process. It seeks
to remove the frustrating waste of money on duplicate systems, extra work,
and manual processes. New technology paradigms often bring opportunities
for centralization. For example, although it may make sense for each department
to have slightly different processes for handling paper forms, no one department
could fund building a pervasive web-based forms system. Therefore,
a disruptive technology, such as the web, creates an opportunity to replace
many old systems with a single, more efficient, centralized system. Conversely,
standards-based web technology can enable a high degree of local autonomy
under the aegis of a centralized system, such as delegated administration.
Network centralization and decentralization
Introduction
The basics
Candidates for centralization
Candidates for decentralization
The icing
Conclusion/exercises
Reproduced from the Addison-Wesley Professional book The Practice of System and Network Administration, 2nd Edition, by Thomas A. Limoncelli, Christina J. Hogan and Strata R. Chalup. ISBN 978-0321492661. Copyright 2007, Addison-Wesley Professional. Reproduced by permission of Pearson Education Inc., 800 East 96th St., Indianapolis, IN 46240. Written permission from Pearson Education Inc. is required for all other uses.
