OK, fess up. You know there are two key truths about your company's data storage: 1) Your company has faced, now faces, or will soon face serious capacity constraints on its application or file servers. 2) Key files are scattered across the enterprise, often difficult to retrieve over the network, sometimes squirreled away on individual users' desktops and laptops. Fortunately, there's a storage technology specifically aimed at file management headaches. That's NAS (network attached storage). Although NAS vendors are beginning to add block-level I/O (input/output) functionality to their devices, NAS is primarily intended to provide file-level access to data. Hang a NAS device off your LAN or WAN (wide area network), and off you go, serving up files to requesting servers, applications, and users.

But, before you go - at least, before you go too fast - think carefully about how NAS fits into your overall application and storage infrastructure. What file sharing needs can it address now? And, what about the future? What role should NAS play as your total stored data grows? Pausing to consider a few words of implementation wisdom will prevent you from creating your worst storage nightmare: an inflexible infrastructure.

1. Feed The Habits Of Your Heavy Users
Identify particular applications and user groups across your enterprise that could benefit from improved access to shared files. Ideal candidates for NAS include workgroups that collaboratively generate data-intensive files, such as Web content, digital video, engineering designs, and animated simulations. NAS devices - particularly smaller capacity snap servers - can be relatively quick and easy to connect to the network. This flexibility allows them to be moved around and rededicated for temporary departmental projects. "Because NAS just plugs into your network, you don't need to retool your architecture whenever you want to use a NAS device to relieve the file serving burden from a server," says Akshay Gupta, general manager of the NAS division for Iomega (San Diego).

For broader access to shared files, Steve Rogers, VP of marketing for Quantum Corp.'s Networked Storage Products Group (San Jose, CA), advises large multi-facility companies to put NAS devices in their branch locations. Having NAS on local LANs enables remote employees to access large data-intensive files, such as videos used for employee training. "Imagine if every employee in every office tried to pull a piece of streaming media from a server on the WAN. That would congest everything," Rogers says. "Instead, you can push those large files to NAS boxes sitting on local LANs on the edge of your enterprise. That keeps remote offices from having to download the file from the central data center more than once."

2. Capture Your Rogue Files
You should also identify individuals who may be creating files that are vulnerable to being locked from access or to being lost altogether. Employees often create and save files that exist in single-copy form off the network. Those files need to be put on the network so they can be accessed and backed up. NAS can provide a safe, centralized harbor. "A lot of critical data is on employees' laptops. In reality, that's where a lot of work is done," says Rogers. "Any person who has been with a company for at least a year is likely to have a GB or more of data sitting on a laptop." Rogers advises NAS users to supplement the hardware device with software that automatically pushes changed files to the network during data dumps.

Dick Vanek, president of NAS vendor Excel/Meridian Data, Inc. (Carrollton, TX), also recommends gathering up decentralized files. "One of the most common uses of our NAS devices is for home directory storage for individual employees' personal documents," he says. "Since NAS supports multiple platforms, all employees' home directories can be put on centralized NAS, which ensures that their files get backed up."

3. Know When Enough Is Enough
Because NAS devices are essentially plug and play and, therefore, relatively easy to install, companies can address immediate point-specific storage needs. As NAS-based file serving requirements begin to exceed the capacity of individual NAS boxes, companies don't need to panic. They can simply plug additional NAS boxes into the network and quickly gain more storage space. However, as with any storage solution, companies should think carefully about how best to manage growth. Continually adding NAS devices to the network can be problematic. As NAS solutions spring up in various corners of the enterprise, it becomes difficult to support them with shared storage resources, such as tape libraries used for centralized backup.

Companies hoping to pool the storage on multiple NAS devices for shared use should also proceed with some caution. "There are software packages out there that allow you to aggregate your NAS storage, but they can be expensive," Gupta says. "So, you have to determine what level of sophistication you can manage. Taking NAS to the next level probably means pooling it with other storage in your data center."

4. Don't Be In SAN Denial
For customers whose scalability requirements necessitate pooling their resources, NAS is likely to become part of a SAN (storage area network) solution. While SANs are designed to manage block-level I/O, they can be used for file-level I/O with the help of a NAS device. NAS heads (also known as NAS controllers) attached to the SAN can serve as file sharing engines. For file-level access, they convert block data and send it out via file sharing protocols, such as CIFS (common Internet file system) or NFS (network file system). "Since SANs move blocks and blocks of data, you can't simply map a drive letter to your SAN and pull up a Word document," Vanek explains. "But, NAS devices can talk to the SAN, where the file data might physically be stored. The SAN administrator can designate blocks of data for the NAS device to use." NAS heads and controllers are fabric aware, which allows them to be plugged into SAN fabric switches so that SAN storage can be allocated to them.

According to Andy Pratt, president and CEO of storage systems integrator Unique Digital, Inc. (Houston), melding NAS with SAN is a must for large companies, where storage requirements tend to grow by 20% to 50% every year. Pratt admits that stand-alone NAS works for small companies, for departments, and for temporary special projects. But, he isn't convinced it can efficiently handle enterprise-level growth. "NAS' file-serving functionality makes it an important peripheral to the block activity on a SAN. If you have extra storage somewhere on the SAN, you can pop a NAS head onto the SAN to make use of it," Pratt says. "If you don't have NAS working with a SAN, you're making a mistake."