Storage Area Networking (SAN) is a lifesaver when it comes to keeping up with ever-increasing storage requirements. But the fatal flaw in most designs, according to this article in Enterprise IT Planet, is that it's too linear. This creates five points of failure along the data path -- the HBA on the server, the cable to the switch, the switch, the cable to the storage device controller, and the device controller. Lose any one of these components to aging or mechanical failure and you might as well try saving data in the employee microwave oven.
The answer to this, of course, is dynamic multipathing, which, like the Internet itself, will usually find a way around a system outage to get your data to its proper destination.
This article is a good place to start, laying out the various components you'll need to install to get the ball rolling.