Storage Area Networks For Dummies®

Chapter 16
Ten Reasons to Use a SAN
In This Chapter
▶ Seeking better storage management and performance
▶ Planning for disaster recovery
▶ Accommodating storage needs and growth
▶ Saving money and resources
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.
You Want Better Disk Utilization
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 future disk
purchase needs because what’s currently in place is used more efficiently.