The era of client/server computing ushered in the challenge of dealing with multiple operating environments. The need for operating systems to communicate has only grown and become more sophisticated. As discussed earlier regarding NAS hardware and software, its architecture of effective OS communications is at the heart of what it delivers. Fortunately for IT professionals, the NAS devices were efficient, encapsulated product bundles and didnt require an in-depth configuration integration effort with other operating environments. This isnt true of SAN technologies (as Chapter 14 illustrated ) with their various hardware components.
This chapter will cover the multiple software components that make up the SAN, a summary of what and how they operate , and a view of fabric operation from the software perspective. At the forefront of this discussion will be the FC switchs operating system, a discussion of the microkernel -oriented set of software services that provides the base functionality for creating the SAN network and switched fabric of interconnections.
The device driver discussion will cover the necessary software drivers that must be available to allow the external node devices to connect to the fabric. Their functions, and how they operate, are integral to the complete configuration of a SAN. Due to their distributed nature, their considerations for design and implementation are dependent on server, storage, and fabric software components.
The most important is the SAN storage software part, given that the entire value of the SAN components leverage a stronger storage position. The SAN infrastructure provides a transparent implementation of most storage media, especially in the area of disk storage arrays and the use of external controller functions necessary in RAID and tape media functions. These include RAID recovery functions, internal array caching, and fault-tolerant features that are integrated with the storage component. Their interaction with the switchs OS, as well as the FC HBA drivers, are critical to the effective configuration and operation of the SAN.
Supporting components part: Additional features inherent with the SAN, but which require additional components to leverage, are data sharing, device sharing, management, and special routing software functions. Although supplied by third-party vendors , the milieu of interrelationships with the Fabric OS and device drivers becomes problematic when implementing these advanced SAN functions.