Chapter 1: Introduction to SANs

Solutions in this chapter:

• Overview of SANs

• Taming the Storage Monster

• Benefits of Building a SAN

• When to Deploy a SAN

• Steps to a Successful SAN Deployment

• Summary

• Solutions Fast Track

• Frequently Asked Questions

Introduction

In the early 1980s, direct-attach disk storage through interconnects such as Small Computer Systems Interface (SCSI) was the standard way to connect to data. This worked well for the amount of data typically handled at the time, and became the standard way to connect high-speed, high-performance storage to computer systems.

However, as computer systems increased in speed and data storage needs increased, the parallel bus architecture of SCSI soon started hitting performance and distance limits. In response to these needs, Fibre Channel was developed to provide gigabit-speed serial networking capabilities for storage. Fibre Channel includes support for the SCSI protocols for storage, the Internet Protocol (IP) for networking, and the Virtual Interface (VI) protocol for clustering, which are mapped onto a network architecture. The Fibre Channel standard combines long distances of up to 10 km, simplified serial cabling over multiple media types, gigabit speeds, and the ability to simultaneously use more than a single protocol over the same wire. These features won adoption for Fibre Channel throughout the 1990s as a replacement for parallel SCSI, and Fibre Channel is now used for most high-capacity, high-end direct storage devices.

With the advent and market acceptance of Fibre Channel as a point-to-point replacement for parallel bus SCSI, a new technique has emerged that combines pure storage usage...