SAN hardware is divided into three distinct parts : the Fibre Channel switch, the Host Bus Adapter (HBA), and the storage device itself. In addition, one must consider bridging, or routing, solutions. Chapter 13 is the continuation of the detailed discussion of SANs started in Chapter 12, which covered their specific architecture. This chapter will explore the hardware components that make up the SAN, a summary of what they are and how they operate , and a view of fabric operation from a hardware perspective.
The switch part is a discussion of the Fibre Channel (FC) switch component that essentially becomes the heart of the SAN. Included will be a discussion of the device attachment options, a brief explanation of operation, and the role they play in the configuration of the switch, consisting of the foundations for configuration, port identification, and interswitch links.
The FC Host Bus Adapter (HBA) is a necessary component to attach servers to a SAN. HBAs have ports that connect to the switch, which play a pivotal role in communicating with the SAN fabric on behalf of the server. There are also considerable differences in HBA software drivers and OS support, as well as options for HBA functions and their interaction with FC switch.
Perhaps their most important aspect, given that SANs are 'storage' networks, is the FC-enabled storage itself. Storage devices for SANs require that they communicate using the Fibre Channel networking standard, consequently their roles and various operations differ in comparison to direct attached storage devices. Included with this discussion will be an orientation to tape media into the SAN, where we identify an additional supporting component, the FC bridge/router, which is necessary in developing a fully functional FC-based storage area network.
We will conclude the chapter with a brief discussion on several important points in the operation of the SAN fabric. From a hardware perspective, the modes of processing and the functions of the physical ports become required knowledge when designing and implementing the SAN. Given that the SAN's heart is the FC switch, the operational aspects of how the switch provides a circulation of data throughout its system cannot be overlooked. SAN switches will be used in multiple configurations (covered in detail in Chapter 18). This requires an initial understanding of the switch-linking functions used for expansion, redundancy, and recovery configurations. Discussions of such can be found in this chapter, as well as in Chapter 15.