Purchasing network-attached storage isn't an easy process. Storage administrators involved in selecting NAS products must look at product features, performance, price, service, upgradeability and other NAS issues. Following
Look at long-term storage needs. With demand for storage booming, administrators should take into account how a prospective NAS purchase (as well as vendor) will suit your long-term storage needs. Explore potential upgrade paths to see how future updates will impact storage performance and costs. More expensive NAS platforms may be more cost-effective over time if they are easier and cheaper to upgrade. Beware of "NAS sprawl" as NAS boxes proliferate over time. If you expect significant NAS growth, consider a clustered NAS product that can combine boxes to scale both capacity and performance.
How will NAS data be protected? It's not enough to simply drop data on a NAS disk. Administrators must define how that NAS data needs to be backed up. One option is internal RAID within the NAS device itself, although snapshot and replication technologies are also common. Using RAID in the NAS device will lower its total storage capacity. If you want to take snapshots or replicate data outside the NAS, adequate storage must also be available to support those procedures as well. To ensure compatibility with your existing backup products, consider a NAS device that supports the Network Data Management Protocol (NDMP).
Are any new skillsets required? There are differences between NAS models and manufacturers. Some NAS boxes run common operating systems such as Windows; others employ a manufacturer-specific OS. IT staff may need supplemental training to install, configure and support the NAS box, and acquiring these new skillsets usually costs money. Up-front lab testing can familiarize your staff with basic NAS operations, enabling them to ask smarter questions during manufacturer training sessions.
Will infrastructure changes will be needed? Once a NAS storage box is online, it will eventually result in heavier traffic on its network segment. Heavy data transfers can overwhelm a LAN. This is particularly true during NAS consolidation projects, during which many distributed file servers are moved to a central NAS box. You should know the implications of traffic changes on the intended network segment, and plan to accommodate any needed upgrades or infrastructure changes. For example, adding a stand-alone NAS to a lightly used network segment may require a move from 100 Mbps Ethernet to 1 Gbps Ethernet (or even 10 Gbps Ethernet in busier environments). The NAS vendor might be able to help with network planning.
How are support and service tasks allocated? Work with the NAS vendor to define the responsibilities for NAS implementation and ongoing support. Know whom to call for help with configuration, operation, diagnosis or replacement -- and know in advance how much that help will cost. Review vendor proposals to be sure that all costs are clearly delineated.
Which applications must be supported? Today's high-performance NAS systems are handling database and other transactional data streams that were unimaginable a few years ago. However, the actual performance provided by such NAS systems can vary dramatically with the applications being supported. Test the prospective NAS system with actual data loads (e.g., transactional data or streaming media) and learn how to tune the NAS to optimize traffic for those important data types.