The networking of data storage arose from needs similar to those that drove the adoption of local-area networks (LANs). LANs are a technical solution to the functional problem of users being unable to share resources. The need to share files, printers, and compute cycles accelerated the advent of the LAN and its widespread adoption in corporations and universities. Likewise, the requirement to logically combine and physically share groups of disks between servers and across business functions has driven the adoption of storage area networks (SANs).
Chapter 1, "Industry Landscape: Storage Costs and Consumption," the sheer numbers of direct-attached environments that are potential candidates for migrations to SANs present a serious management headache to IT storage teams if the environments themselves are to remain homogeneous (not to mention a huge financial boon to a select few hardware vendors). Interoperability has historically been low on the list of vendor initiatives, with a large portion of disk arrays shipping without a management interface or an SNMP Management Information Base (MIBs). This is partially due to the tremendous amount of work that is required to redo or modify data schemas and MIBs . It is also safe to assume that while the storage market was booming, there was little justification for storage vendors to provide mechanisms that would enable better management of storage devices. Disk and Fibre Channel switch vendors recently made inroads with manageability by opening their APIs, or at least sharing them to some degree with software developers, although many are still behind the customer demand curve as far as producing software tools that provide the exact desired functionality when it comes to management of storage devices.
Interoperability continues to be an issue for the immediate future, but there are still financial benefits to implementing networked storage solutions. As shown in Chapter 1, the issue of utilization is the primary cost factor with DAS. From a Chapter 1 mentioned the creation of a storage recovery program dedicated to the analysis of application utilization trends. As part of the storage program, subject matter experts should have an analysis of table spaces and data usage trends as their charter. Attention to these details should ensure that the application's requirements match the storage solutions deployed and that the applications themselves appropriately use the storage allocated to them.
In addition to a storage recovery program, a storage consolidation program assists in increasing the financial benefits of a Fibre Channel environment. The migration from DAS to SAN storage paves the way for storage consolidation. Many DAS environmentsespecially those in which the disk units near the end of their depreciation cyclehave smaller disk drives (typically 36 GB, 18 GB, or even 9 GB). 73 GB, 146 GB, and 181 GB disk drives are capable of rotational speeds equal to or superior to that of the smaller drives and the increased capacity in a single footprint easily justifies consolidation. A consolidation project can also alleviate hardware and software maintenance bills by facilitating the decommissioning of older, smaller capacity disk storage units.
The implementation of a SAN framework, when coupled with a consolidation effort, can lead to collapsed points of management, which alleviates some labor costs and releases precious datacenter space.