Introduction to Distributed Systems

Distributed systems have changed the face of the world. When your web browser connects to a web server somewhere else on the planet, it is participating in what seems to be a simple form of a client/server distributed system. When you contact a modern web service such as Google or Facebook, you are not just interacting with a single machine, however. Behind the scenes, these complex services are built from a large collection (i.e., thousands) of machines, each of which cooperate to provide the particular service of the site. Thus, it should be clear what makes studying distributed systems interesting. Indeed, it is worthy of an entire course; here, we just introduce a few of the major topics.

Challenges with distributed systems

A number of new challenges arise when building a distributed system. The major one we focus on is failure; machines, disks, networks, and software all fail from time to time, as we do not (and likely, will never) know how to build “perfect” components and systems. However, when we build a modern web service, we’d like it to appear to clients as if it never fails; how can we accomplish this task?

THE CRUX: HOW TO BUILD SYSTEMS THAT WORK WHEN COMPONENTS FAIL

How can we build a working system out of parts that don’t work correctly all the time? The basic question should remind you of some of the topics we discussed in RAID storage arrays; however, the problems here tend to be more complex, as are the solutions.