Building a NAS system involves many different considerations. John Webster, principal analyst at the Data Mobility Group, and Mike Fisch, a technology acquisition consultant at the Clipper Group, offer seven key questions to address before you start spending money.
1. What is the operating system (OS) in the NAS box?
Webster says that NAS devices run on OSs ranging from the familiar -- such as Windows or Linux -- to those crafted for the vendor's own devices. Being aware of OS issues can help you determine what you'll likely need in terms of support or skills development. "You should think through where the handoff is between vendor support and support from the supplier of the operating system, such as Microsoft," Webster explains.
2. What environment will you place your NAS system into?
You should have a clear idea of whether you will run it as a standard file server or whether you'll be trying to 'stretch' its capabilities to support the demands of a database environment. "If you want to use it for database operations, that's fine, but you need to be aware of potential performance constraints," Webster says. He explains that some organizations are willing to adopt NAS in a so-called 'poor man's SAN' configuration with a dedicated 10 gigabit Ethernet link going directly to the NAS box -- mimicking some of the aspects of a SAN. "A lot of people will claim that works well for them, because it provides a simple management structure."
Furthermore, Fisch says, would-be NAS customers need to consider whether their NAS should or could attach to a SAN on the backend or if it will remain standalone. "I'm thinking about the degree of storage consolidation that they want to implement because integrating SAN and NAS with a NAS gateway can potentially provide a greater degree of consolidation," he says.
3. How fast will your needs grow?
Webster explains that companies often fail to consider how much additional capacity they will need in the years ahead. He says that developing growth estimates and then looking at whether the NAS technology and the vendors you are considering offer capabilities that will adequately support that growth.
4. How will you back it up?
Fisch says it's important to take a good look at what you are doing and perhaps at what you should be doing in terms of backup. What will it take to provide snapshot and data replication for your operation? "If you want more sophisticated capabilities then that will influence what you buy," he explains.
One thing that can help clarify such decisions, according to Webster, is whether a vendor offers support for the Network Data Management Protocol (NDMP) -- the standard protocol for matching backup products to NAS technology. "Be sure to check the version of NDMP, too, because there are significant differences among them," he says.
5. What are the extras?
Beyond the basics, there are sometimes substantial differences between products. So, cover the bases of your 'must have' features and then look at what else you can get for your money.
6. What's the performance and will it be enough?
Finally, Webster says it's worth reviewing speeds and feeds because "the people who are happy running NAS in a database environment admit they aren't usually looking for anything too fast or their performance bottleneck is somewhere else."
7. Will the NAS participate in a global namespace (e.g. NuView, Acopia, NeoPath) or present its file systems directly to clients?
"This is an up-and-coming area," says Fisch, explaining that new global namespace solutions solve a lot of problems by supporting management consolidation and better utilization. If you use this capability, he says, "some of the management and even the migration and replication might take place at the global namespace layer, which could allow adoption of a less sophisticated NAS system."
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About the author: Alan Earls is a freelance writer in Franklin, Mass.
This was first published in September 2005