NAS And SAN Vs. NAS Dr SAN.

The triumvirate of Information Technology (IT) building blocks-computer processing, network bandwidth, and storage-is linked such that an advance in any one produces pressure on the other two. So as broadband networking becomes more prevalent and the price of computer processing continues to plummet, the pressure to improve storage and storage management solutions doubles in its intensity. In the hyper-competitive Web-economy, 100 percent reliability and 24x7 availability are business requirements. Add the continual migration of enterprise applications to the web, e-commerce transactions, and swelling multimedia content, and you see that Internet-driven storage demands continue to accelerate at an alarming rate. In fact, industry analysts put the total amount of information currently stored in the United States somewhere around 500,000 terabytes with this number ballooning to between four and five times that total in three years.

To face the ever-growing storage flood, business and government enterprises are increasingly turning to a pair of storage solutions: Network Attached Storage (NAS) and Storage Area Networks (SAN). While these solutions are by no means newcomers to the market, the exponential increase in demand for storage has brought these formerly specialty products to the forefront. Their rapid ascension has brought with it a slew of myths and misunderstandings. Paramount among them is the tendency to view NAS and SAN either as competing technologies or as the same technology when neither situation is really the case. As it stands, NAS and SAN are distinct technology solutions for handling disparate storage problems.

The I(ns)/O(uts) Of NAS And SAN

It is easiest to think of NAS as a specialty appliance, or a series of specialty appliances, that have no other role within the system than to store and process data. Capable of being connected anywhere on the network, a NAS device is essentially a stripped-down server particularly well suited to workgroups with need for additional storage. These standalone devices run their own integrated hardware and software and typically support discreet storage requirements without requiring the overhead associated with installing a new server.

Unfortunately there is no similar, simple way to think of SAN. Instead of coming in a simple box that can be attached to a network, a SAN is a system architecture composed of speedy network connections (Gigabit Ethernet, Fibre Channel, etc.), storage appliances (RAID, tape libraries, etc), and most importantly, software applications. SAN solves the LAN-to-storage bottleneck by using the high-speed network connection to centralize storage so that individual servers can access the storage devices as needed-which translates into more efficient use of storage space and much improved scalability.

NAS appliances are particularly attractive to the market at this stage because they offer the most dramatic increases in storage capability (some exceeding 700GB) with the easiest integration and the lowest Total Cost of Ownership (TCO). To companies facing immediate, pressing storage problems, NAS offers a robust, ready, and reasonably easy solution. Despite the fact that, at the time of this writing, the cost for NAS appliances exceeds those of server solutions, this is countered by the ease of implementation, elimination of operating platform software, and the efficiency associated with removing file-storage responsibilities from the server. As such, the TCO associated with implementing these devices is significantly lower than setting up and managing standard servers-an important consideration in light of today's IT labor shortage.

Though SAN is clearly a robust technology at this stage in its development, it lacks the ease of use inherent with the NAS appliances. Moreover, at this time, there are no universally recognized standards for compatibility and interoperability among SAN systems, a deficiency that has led the federal government to lag in its implementation of SAN storage solutions. More than any other factor, it is this lack of interoperability that has given rise to the greatest of the NAS/SAN myths.

Because NAS is so immediately responsive to the urgent storage needs of the market, providing robust storage with simple installation and cost-effective management, it is perceived that the fantastic demand for NAS will disrupt or eventually eliminate the demand for SAN. Moreover, those who are concerned that the SAN will eventually become both more usable and robust than the NAS worry that the short-term patch will eliminate the possibility of implementing a better long-term architecture solution somewhere down the road. In some cases, this fear is preventing IT managers from taking steps to immediately address their storage needs by implementing NAS.

While it is true that NAS offers an ease of use not found in the complex SAN storage architecture, the application of the NAS appliance is only cost- effective as a replacement for the server-based storage solution. Relative to the SAN, NAS requires processing power and bandwidth from the network it serves, and though you might potentially store thousands of gigabytes in a series of NAS appliances, the data traffic would bog down the network to the point where it would no longer be usable. Along the same lines, including every client workstation in the SAN data stream would prove both pointless and expensive.

Useful Definitions For NAS And SAN: Workgroup Vs. Enterprise

Noting the ease with which you can fall into a fallacy about the nature of NAS and SAN, the best way of understanding these storage technologies is in their use and application. NAS appliances, with their ease of use and robust storage capability, are perfectly suited to meet the storage demands of the workgroup or department. The SAN architecture, conversely, with the high-speed connection and the ability to access petabytes of information stored in various media, is best implemented as an enterprise storage solution.

The NAS is designed specifically for serving files and is both balanced and tuned for that particular job. Integrated into a workgroup network, it improves data performance and availability by removing the server, which is already tasked with a series of other duties from the file-sharing role. Moreover, the NAS installs in minutes, can be managed using a web-browser, and is available even if the applications server is down. The result is faster responses, fewer outages, and continuous access to files.

The SAN is designed to store and to move large amounts data in and around a central location that is independent of the corporate network and primary server structure. The storage is then integrated with the primary network through a high-speed gigabit Ethernet or Fibre Channel connection to facilitate access for all members of the enterprise. Applied to a research organization or a library, the SAN would provide the ability to store an enormous amount of information without burdening the entire LAN with its transmission, processing, and management. Applied to a Fortune 500 company, the SAN would allow the enterprise to maintain large schematics or catalogs in a central location to enable global workgroups to work on a project around the clock.

The localized position of the NAS and the centralized architecture of the SAN are integrated to meet specific storage needs. In nearly every case, NAS and SAN are not interchangeable as storage solutions because each technology has such a specific role to play. Substituting one for the other due to the easy confusion typically results in a storage solution that is either needlessly complex and expensive or simply inadequate to the task at hand.

If you cannot deliver 24x7 reliability or the content that your customers want, the Web will make it easy for them to go elsewhere. Avoiding storage problems depends upon clearly understanding what functions your storage solution is intended to perform and translating those needs into the components to meet them. Make sure that you find solutions provider who has access to the full range of NAS and SAN technologies with the right support behind them. Just bringing the component parts to the table is not enough. Without the understanding of what technology to implement or the professional staff to integrate the components into your enterprise, your storage solution will be empty.

Shaf Mohebbi is the vice president of sales and marketing at BITCO Enterprises (Ashburn, VA).