In this chapter, I cover the top ten reasons why companies purchase a storage area network (SAN) rather than sticking with the traditional but tried-and-true method of buying large servers with tons of internal disk space. After reading through this chapter, you'll have a good idea about whether implementing a SAN makes sense for your company.
The number one benefit from installing a SAN is better disk utilization. When all your storage is tied together through a centralized storage network, you gain the capability to manage everything as a single entity. This lets you slice up the central pool of storage resources at the network level and assign that storage more intelligently to the servers that need it. The approach to disk management without a SAN is to buy tons of disks and stick them in huge expensive servers so that you can grow into them. All the disk space that's not currently being used is wasted until you need that space.
Better utilization of disk resources means less disk space is sitting around doing nothing but taking up power and cooling.
Many companies that still use storage internal to the servers — also known as direct attached storage (DAS) — typically report storage utilization rates of 40 percent or less. Those who have implemented SAN technology have reported upwards of 80 percent utilization. Using 80 percent of your storage leaves 20 percent free for growth. This creates a solution that defers ...