The short, hard-and-fast rule of IT, and especially storage, is that there are no short, hard-and-fast rules. And this is the case when asking the question whether or not you need network-attached storage (NAS).
First, let's look at why an organization shouldn't introduce NAS. One of the primary reasons for not introducing NAS is increased complexity. While the NAS devices of today have been tuned for ease of use, they still require more management and administration than a hard drive tucked away inside your server. Some new issues you'll have to deal with include network bandwidth, latency and the device's interface.
In addition, there's the increased acquisition cost -- no matter what a NAS vendor tells you. Buying hard drives and sticking them into a server costs less than a networked storage device. However, keep in mind there is more to the cost of a device than simply acquiring it.
How the device scales and how much it costs to scale it could be considered a con. Some devices have a maximum number of spinning disks they support; some do not support expansion shelves, and the cost to upgrade to a bigger model can sometimes be substantial.
There are some scenarios where adding NAS would not be advantageous. Some questions to ask that will help you decide if NAS is a good fit include:
- Do you have the resources to cover the care and feeding of a new NAS device?
- Does your network span multiple locations with sub-T1 (1.5 Mbps) up and downstream bandwidth between them (the cable company's internet is normally 768 upstream, and DSL is roughly the same)?
If so, moving data into a central location on a NAS may create network bottlenecks. Just think about how long it takes to upload that 20 MB PowerPoint over your home ISP, then think about the number of people in your offices trying to do that on the same wire at the same time.
Another situation where you may want to hold off on deploying NAS in your environment is if your data growth is less than 15% yearly. You should consider how much valuable data you are actually storing. Some businesses use the same documents repeatedly and don't really increase the amount of useful line of business data by much. Fifteen percent is the magic number I've seen in the small to midsized business (SMB) space, however, your situation may vary. Given the three-year depreciation lifecycle of a device, 15% of 2 TB yearly is approximately 1 TB (300GB/year).
The advantages of NAS
The advantages of having networked storage are rather straightforward. NAS devices are relatively easy to maintain, offer "set and forget" configurations and some even offer "phone home" services where the device alerts the vendor when a part needs servicing. Many of today's entry-level NAS devices even have redundant components allowing for failover and hot swap of key components.
NAS devices integrate into a wide variety of environments rather easily, allowing multiple, simultaneous access from disparate computing platforms (Windows, Linux, Apple, etc.) using a myriad of file sharing protocols (NFS, CIFS, etc.). Adding capacity is easier, too, as most NAS vendors only require a short downtime window to plug in new shelves of disks. And, for the most part, there are no specialized skills required to run a NAS device.
You should seriously investigate deploying NAS when you have valuable data assets exceeding 2 TB on hard drives throughout your network. If you spend more than 20% to 30% of your time tending to localized storage needs, you should put acquiring NAS on your shortlist for the next quarter. You can make far more effective use of your time by centralizing your important data assets, eliminating time-consuming touch points and centralizing your ability to implement controls on your data.
Most of today's NAS devices come in minimums of 2-plus TB. If you only need 1 TB or so, SMB-level NAS really won't fit your needs. There are prosumer-grade NAS devices currently on the market that would better serve your needs, such as the Buffalo Technology TeraStation, Data Robotics Inc. Drobo and products from Iomega (now owned by EMC Corp.).
If you plan to implement production server virtualization, then networked storage is a must. Virtualization technologies love networked storage, and your virtualized infrastructure will become much more robust when it is backed by a NAS. Networked storage opens up the world of VMotion (the process of migrating a virtual machine from one host to another without downtime), as well as high-availability (HA) clustering (a la Microsoft Clustering Services), allowing you to realize the full potential of a virtual infrastructure.
About the author: Tory Skyers is a senior systems engineer for Prudential Fox & Roach Realtors, an independently owned and operated member of The Prudential Real Estate Affiliates Inc. He frequently speaks at conferences such as Storage Decisions and also contributes regularly to SearchStorage.com's blog called Storage Soup.
This was first published in October 2008