The benefits of implementing a SAN are clear: you can improve storage utilization, offload CPU demands, and lower the cost of application support. Because business needs change over time, you need to make sure that your SAN is strategically architected for the highest visibility, scalability and control, and that it can leverage storage and computing resources across the enterprise. Taking a strategic approach to building the SAN ensures that your company will get the most out of it, now and for the long term. Here's a quick blueprint for thinking strategically about building your SAN, broken down into four major components: storage, computing, network infrastructure and software.
The storage arrays are SAN's most tangible resource. They're also often the most expensive, in both the price-per-megabyte and ongoing ownership costs. A thorough grasp of the line-of-business requirements helps administrators correlate the right storage for each application, yielding the best return on investment. For example, there's a big difference between SCSI arrays built for enterprise-class performance and scale, and an ATA disk that offers radically different price/performance metrics. Applying the appropriate storage resources with the ability to manage each as time goes on is critical to SAN value.
SANs relieve servers stressed for processing power and storage capacity. The opportunity to offload not only storage, but also CPU-intense
Historically, the network connectivity portion of the SAN has been a tag-along item with the storage array. Each time IT purchased new storage, it would be accompanied by network components (such as switches, etc.) to allow connectivity to the application hosts. This incremental approach to storage networking was appropriate for a while, as SANs were usually tactical rollouts associated with particular applications. However, the end result of the project-by-project rollout leads to disparate SAN "islands" that don't allow for the long-term consolidation benefits that SANs enable. By designing a storage network backbone that is independent of particular storage resources or applications, the entire SAN is more scalable and adaptable to change. When designing a storage network, consider fundamentals that will serve through several data center life cycles, and lay out a working timeline for the future.
Consider, at a minimum, a 3-to-5 year SAN strategy. This strategy should include a network infrastructure that can scale to accommodate not only growth, but additional rates, protocols and services. An independent network infrastructure, not linked directly to a storage purchase, will make it easier to buy the best type of storage for unique application requirements as they emerge.
Finally, consider visibility and control. Knowledge and awareness of the network are essential to peak performance. With the ability to understand traffic flow and apply network bandwidth control, all the effort put into configuring the right storage and computing resources can be leveraged through the enterprise.
Storage costs are best evaluated in the context of what it costs to maintain storage once it's acquired. The current multiplier for acquisition to management is about 5-7x, which means for every dollar spent on storage acquisition, another $5 to $7 (on average) is spent maintaining it. Reduced management costs are an important value driver for SANs, and software is at the root of it. The right SAN software, specifically storage resource management (SRM) software, significantly reduces the cost of storage ownership through the ability to allocate, provision, control and secure networked storage.
Design for change. As with most technology applications, SANs are most effective when able to adapt to the ever-changing priorities and patterns of the business. Look for SAN components that are open, flexible and highly accessible through useful interfaces. Although SANs have made great progress in the way of interoperability, it is still important to investigate both the current and long-term plans from vendors to support industry standards. Make sure you, as the customer, stay in the driver's seat based on your own best practices, goals and technology timelines.
About the author: Eric Blonda is director of product marketing at Sandial Systems Inc. in Portsmouth, NH. He can be reached at firstname.lastname@example.org.
This was first published in July 2003