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As articulated several years ago, the mission of the Storage Networking Industry Association (SNIA) is to ensure that storage networks become efficient, complete, and trusted solutions across the IT community. While this is a noble goal for a vendor association, it implies that SANs have not been efficient, have been incomplete, and have not established widespread trust within the broader end user community. While all of these assumptions are still valid, significant progress has been made over the five years of the SNIA’s existence.
Efficiency of SANs
Efficiency is a broad category that spans everything from performance to ease of implementation and management. SAN technology has demonstrable efficiency in terms of performance. Host bus adapters (HBAs) operate at wire speed and with minimal CPU utilization. SAN fabrics offer high performance 1 and 2 gigabit per second (Gbps) switching, as well as the ability to aggregate interswitch links to optimize throughput in a multi-switch fabric. SAN-attached storage devices offer multiple 1 and 2 gigabit ports and high performance RAID controllers and caches that minimize the latency of read and write operations.
New IP storage technologies have also demonstrated efficiency in terms of wire-speed throughput and optimum utilization of local and wide area IP networks. With 4 gigabit and 10 gigabit interfaces on the horizon, even greater performance is expected, making SAN technology the obvious choice for efficiently moving block data from servers to storage assets.
The same level of efficiency has not been reached, however, in terms of ease of implementation and management. Beyond the underlying transport, storage is a complex discipline that has required manual administration to create, assign, and monitor storage resources. This inherent complexity is exacerbated by a storage network, since the ability to share storage assets between multiple servers also requires close monitoring of asset assignment.
Installing and optimizing a SAN configuration is far more complex than a comparable direct-attached solution, but once established, SANs offer significantly more value in terms of consolidated storage, backup, and other applications. The result is that while customers may feel some new pains in implementing SANs, many old and familiar pains thankfully disappear.
Making SAN solutions efficient requires addressing all the remaining inhibitors to configuration and management. The SNIA Storage Management Initiative (SMI) is attempting to resolve inefficiencies in storage networking by offering a uniform management interface that spans all vendors and all aspects of storage transport and placement. This goal has been central to the recent activity of the SNIA and a major beneficiary of SNIA funding and volunteer effort. The SMI effort has been elevated as an official SNIA Architecture, with shepherding by SNIA through ANSI and the appropriate standards bodies.
In the long term, a viable SAN will offer the dual benefits of efficient performance and efficient management. In the near term, customers frustrated with the current inefficiencies of SANs can expect steady progress towards resolution, but no immediate remedies. SMI and virtualization initiatives are attempting to mask the complexity of SANs and simplify management, but these are intricate problems that cannot be fixed overnight. Multi-vendor cooperation between storage, switch, and software suppliers is at least accelerating the development of new management solutions, particularly compared to the sluggish performance of vendors on this front a few years ago.