NAS Knocks At The Data Center Door

Network attached storage (NAS) has always been fairly friendly to users, particularly in terms of flexibility, simplicity, and cost. Plug a NAS appliance in here, plug one in there - anywhere on the network - and you have an immediate burst in storage capacity, available for multiple applications.

The single-purpose design of traditional NAS hardware (basically, hard disk arrays configured for file serving) has made NAS relatively easy to deploy. And, it has made NAS particularly attractive for departmental and SME (small to medium enterprise) use, where IT staffing is often limited. According to Randy Kerns, senior partner with storage consultant Evaluator Group (Greenwood Village, CO), "NAS devices have commonly been purchased by people who aren't storage professionals. Typically, they are overworked systems administrators trying to also handle data storage."

In addition to flexibility and simplicity, cost continues to make NAS an attractive proposition for capacity-strapped organizations that need to scale up. As Jeffrey Kattar, business development manager for NAS provider Inception Technologies, Inc. (Andover, MA), observes, "Decreasing prices in the disk drive market have enabled a quantum leap in NAS capacity and performance. In the past, you would have to spend at least $100,000 to get a terabyte of capacity. Now, depending on what you want to do, you can get a terabyte of capacity for under $15,000." Kerns notes that cost is the driving force behind both the development and the adoption of NAS devices. "It used to be that companies would be dazzled by the shiniest new technology," Kerns says. "Now, they are much more focused on productivity and cost. So, most of the new NAS products coming out today reflect an awareness of the need for an economic justification."

But, even as NAS vendors remain committed to offering affordable, easy-to-deploy storage solutions, the capabilities and uses of NAS devices are, in fact, expanding. No longer are the applications for NAS limited to network file sharing. NAS is, in fact, showing up in environments once thought to be the exclusive province of SANs (storage area networks). That's because vendors are designing NAS devices that can contribute to the storage consolidation requirements of enterprise storage networks and data centers.

NAS Partners With SAN
The SAN/NAS convergence that has been predicted for several years is now actually happening. The common way of envisioning the convergence has been to view NAS as the file serving piece of a storage infrastructure and SAN as the block-level data mover. Hence, there have been repeated claims made about SAN and NAS being complementary rather than competing architectures. But, some NAS vendors are taking the notion of a SAN/NAS convergence right down to the level of the features built into NAS devices. They are designing NAS devices that offer, for instance, block-level access, enabling those devices to store and serve not only files but also raw data for databases. Says Keith Brown, director of technology and strategy for NAS vendor Network Appliance (Sunnyvale, CA), "In a year or two, the SAN versus NAS argument will be off the table. Most storage systems will have all of the capabilities rolled in."

As Evaluator Group's Kerns notes, Network Appliance has recently announced a product that can handle both block and file access. "They've taken their existing proprietary system and added a software layer that allows you to plug in Fibre Channel cards for block access," Kerns explains. Kerns is taking a wait-and-see approach when it comes to the ability of such devices to be smoothly integrated into heterogeneous SANs. Nevertheless, he acknowledges that by working on the so-called convergence, NAS vendors are addressing end users' concerns about having to learn two different approaches to scaling and managing centralized storage. "Vendors will have to re-educate customers - particularly storage professionals working in enterprise data centers - about how NAS can work for block access," says Kerns. "Those people tend to deploy SANs because, traditionally, SANs have scaled better than NAS."

Key to NAS' ability to take on SAN-like responsibilities is software that can manage storage pools across multiple NAS devices. "With NAS' inherent ability to add capacity by combining with other NAS devices, people will need to use aggregation software," says Kattar. "That will allow them to add storage without jumping through hoops to do it."

NAS Prepares For Serial ATA
As it stretches the boundaries of its functionality, NAS begins to look less and less like a departmental solution. In large, distributed computing environments, including global ones, NAS devices can be strategically placed further and further toward the edge of the enterprise. "Most big corporations have a number of remote offices that don't have their own IT resources," says Brown. "But, people in those offices still need access to data. NAS enables you to remotely deploy storage easily."

The ease of remote deployment also makes NAS a potentially valuable resource for secondary storage in an off-site data center. The snapshot capabilities built into many NAS products already on the market mean that NAS can be deployed as part of a business continuance or disaster recovery solution. "The majority of NAS products do snapshots well," Kerns confirms.

Finally, NAS can play a key role in allowing companies to maintain larger amounts of key enterprise data online. Again, continued drops in the cost of disk-based storage will be a significant factor. Like many industry observers, Inception Technologies' Kattar is keeping an eye on developments with IDE (integrated drive electronics)-based devices. "The biggest thing on the horizon is the hot swappability of IDE drives, which will make devices that use them competitive with SCSI [small computer system interface]-based systems," Kattar says. "Further down the road is serial ATA [advanced technology attachment]. Serial ATA offers the cost advantages of IDE drives with significantly better performance."