Stashing

Why build a distributed system? Why not spend the same money and effort on a centralized system? There are several attractions to sticking with a centralized system.

a) It’s easier to build. It doesn’t need much research to build powerful centralized systems. The technologies are well understood, even if the requirements include high availability in the presence of failures.

b) It performs better. A distributed system necessarily involves a static partition of the total resources into smaller boxes. A centralized system can partition dynamically, responding to the time-varying offered load.

c) It’s easier to manage. You employ one system manager for the centralized system, and he does the management as his job, what he gets paid for. Distributed systems typically make each user be a system manager, even although it’s not viewed as a productive part of their job. This isn’t a necessary consequence of distribution, but it seems to happen with today’s systems.