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Conclusion
This chapter covered the basics of using financial metrics to measure the business impact of storage networks. The payback method was introduced to build familiarity with the concepts of financial evaluation. The payback method is generally used only for short-term projects with small budgets. ROI, NPV, and EVA were introduced as tools that are most frequently used for evaluating projects with larger budgets and longer time horizons.The most critical piece of the DAS-to-SAN migration business case is determining the current storage TCO. Even if this number is just an approximation, it serves as the basis for ROI and NPV analysis. Cash inflows are measured as the value of the increase in storage utilized.Value cases for consolidation projects are built primarily on cost avoidance figures for maintenance bills and decreases in facilities costs. Consolidation, coupled with SAN migration, further increases the net benefit of migrating to storage networks.NAS and iSCSI implementations take advantage of pre-existing IP infrastructure to lower the TCO. Migrations from DAS to NAS and from DAS to iSCSI can also significantly help increase allocation utilization.The next step in executing a storage vision is tactical. After the value case is built and the solution is funded, the challenges involved with implementation follow. Available best practices can help navigate the array of possible pitfalls, but true implementation success requires an understanding of your environment and its application requirements in addition to the less technical facets, such as negotiating, pricing, and staffing your project. Best practices for implementing storage networking strategies are covered in Chapter 4, "How it Should Be Done: Implementation Strategies and Best Practices."
