SAN Buyers Guide: Part I
Today, many enterprises that are currently working in a direct attached storage (DAS) environment, are investigating advanced storage options and implementation plans to move to the centrally pooled storage arena by creating and deploying their first storage area network (SAN). Storage area network (SAN) technology provides a variety of business and technical advantages over DAS and other data storage architectures (networked attached storage (NAS), etc.). Most enterprises who are considering a move to their first SAN, recognize the technical or business value, but they often need further justification for determining their needs, preserving the required infrastructure investment and coverage of hidden costs (such as software, warranties, etc.). With that in mind, this article is a general buyers guide for determining the minimum amount of resources and equipment needed to create your first SAN in order to achieve a financial payback (return on investment (ROI)); and, justification for moving from your current DAS environment to a SAN system.
Business Case AnalysisA solid business case analysis should be performed in the planning phases of SAN design and justification. The reason for this is that a SAN can radically impact the operational enterprise infrastructure. Also, the cost of a SAN infrastructure itself (without considering the cost of storage arrays) is often very high. In other words, without proper planning and impact analysis, the very high cost of Fibre Channel (FC) SAN technology components may inadvertently drive away some enterprises that should really be considering this technology.
Furthermore, another insufficient rationale for creating and implementing Storage Area Networks is the possibility of financial savings by itself. Other pooled storage architectures and SANs can be expensive. They also add complexity to enterprise operations and infrastructures. Quite often, in order to improve staff skills and the adoption of robust operating procedures, new processes and technologies are required; as well as, training. Also, other storage systems attached to SANs are more expensive than attached disks on !ow-end servers or just a bunch of disks (JBODs).
Today, SAN creation and deployment is an investment, and not necessarily a cost-saving action. As more second-generation SAN adopters create and deploy this technology, more thought is required by the enterprise for the investment rationale; and, demands for improved ROI are growing.
Clear investment payback and total cost of operation (TCO) improvements by enterprises have validated the various SAN buying models presented in this article. It is also plausible that the data may identify the SAN as a major cost-saving technology by early 2003, as more empirical data becomes available and is certified by more users. Thus, as further empirical data is made available, these SAN buying models are being fine-tuned by numerous enterprises.
Open Systems ArchitectureSince many enterprises today have adopted an open architecture (a topology-independent approach to SAN design, creation and implementation), not all corporate IT departments have to consider complex Fibre Channel switch or director technology to achieve the benefits of central storage pools. In order to assist in early preparation for cost, benefit, and acquisition approval of new infrastructure technology, the enterprise should create buying and return on investment (ROI) planning models, as part of its general SAN planning methodology. With different topologies, most enterprises have found that ROI has a different payback and impact. Also, for each IT infrastructure, ROI is different. Therefore, in order to help each enterprise design, create and implement the SAN solution that best fits its operational, technical, and financial requirements, the preceding ROI knowledge must be used routinely.