Much more than an external hard drive, the latest NAS devices have transformed themselves into full-featured, multi-purpose computing devices that can act as media, print, and file servers; surveillance devices; web hosts; and even file-streaming servers for mobile phones. Indeed, the term "network attached storage" is probably a misnomer. The new NAS, with its own chipset, operating system, and network connectivity options, is essentially a "network attached server."
In fact, if you have a spare PC with a CD-ROM and hard drive that you'd like to press into service as a NAS, you can set it up with FreeNAS, a FreeBSD Unix-based distribution that supports the most common NAS protocols, server processes, and applications. But considering the low cost, quality assurance, and bundled capabilities of the commercial alternatives, it's probably worthwhile to spend your time figuring out which off-the-shelf hardware is best for your needs instead of experimenting with the build-your-own approach.
NAS devices can be evaluated on several dimensions, including storage, PC backup, NAS backup, and server-based applications.
How Much Storage Do You Need?
Unlike an ordinary external hard drive connected directly to a PC, network attached storage can be shared across a network by multiple users using multiple devices. Although NAS devices typically have an upper limit to user accounts, groups, and concurrent users, these limits are usually set rather high -- in the hundreds or even thousands -- befitting the origins of NAS as an enterprise and workgroup technology. The real limitation is available disk space.
For each computer you own, you should plan to perform incremental file backups, including a full system image of your operating system, programs, settings, and files. That way, if the PC hard drive fails, you can simply get a new one and restore from the image. To estimate the size requirements, add the size of your documents folder to the total hard drive space used for each of your systems, and multiply by a factor of three or four.
Next, estimate your rate of data growth. One terabyte of storage, or 1,024 gigabytes, holds about 680 movies downloaded from the iTunes Store. So, if your family downloads three movies per week, it would take you about four years to fill a single terabyte. But if you're also adding other file downloads, or if someone at home is engaged with music composition, video production, 3-D graphics, or other storage-intensive applications, you'll need to plan accordingly with a larger target for disk space.
Give yourself plenty of room: One terabyte sounds like a lot of space, but so did 80 gigabytes just five years ago.
If you simply copy your files to an external hard drive and then delete the originals, you're gambling that the external hard drive won't fail. Over time, you'll lose that gamble. By contrast, if you use disk mirroring (RAID1) or disk striping (RAID5) to store your data across multiple drives, a single disk failure isn't a disaster, but instead an advance warning to install a new drive.
Accordingly, I would recommend a dual-bay NAS device for RAID1 disk mirroring as a minimum specification for anyone considering this technology. This means that if you need 1 TB of storage, look for a 2-TB NAS solution supporting two separate 1-TB drives.
While it may seem extravagant to purchase twice the hard drive capacity than you expect to need, just remember that for every gigabyte of RAID-protected data moved to your NAS, that's a gigabyte you can delete from your PC's primary hard drive, freeing up space for easier defragmentation and better performance. Your laptop's hard drive should be a digital briefcase for the files you're working on now, not a digital safe deposit box containing everything you've ever done.
Starting with RAID1 on your NAS, you can safely delete files on your PC, and then more easily upgrade operating systems, try new applications, or download new content without worrying about disk space. It's a liberating experience.
Although RAID5 costs more to implement up-front and has performance disadvantages relative to RAID1, it provides higher levels of data protection and becomes quite cost-effective for larger implementations. Here are some sample calculations comparing the QNAP TS-210 two-bay (using RAID1) with the QNAP TS-410 four-bay NAS (using both RAID1 and RAID5), with 1-TB and 2-TB Western Digital Caviar Green hard drives:
|NAS||Hard Drives||RAID||TB Available||Street Price||Cost per TB|
|QNAP TS-210||2x1TB||Level 1||1 TB||$420||$420|
|QNAP TS-210||2x2TB||Level 1||2 TB||$540||$270|
|QNAP TS-410||4x1TB||Level 1||2 TB||$720||$240|
|QNAP TS-410||4x1TB||Level 5||3 TB||$720||$240|
|QNAP TS-410||4x2TB||Level 1||4 TB||$960||$240|
|QNAP TS-410||4x2TB||Level 5||6 TB||$960||$160|
Prices vary widely by manufacturer and disk size, but the basic math points to buying the largest available hard drives that fit in a given unit. While RAID5 is less expensive as storage needs increase (not including the higher power usage), it's most appropriate for read-only applications such as media servers. If you expect to use your hard drive capacity for write-intensive applications such as content generation, file downloading, or database access, RAID1 may be a better fit.
Many vendors, mainly traditional storage companies such as Buffalo, Iomega, and Seagate, provide NAS devices with pre-installed hard drives. Other vendors, such as QNAP, Synology, and Thecus, require you to purchase and install hard drives from a list of compatible devices. That aspect shouldn't put you off much, since NAS devices have been designed to make it easy to install or replace hard drives.
Aside from hardware characteristics, NAS vendors also differentiate their offerings based on the type of backup software included with the device.
However, for home networks, you really don't need external software to manage backups. All you have to do is mount the NAS onto your regular file system such that it appears as an attached hard drive. Then, Windows XP users can run the NTBACKUP utility and Windows 7 users can run the Backup and Restore control panel.
If you want or expect to support Macs with your NAS, check that the device supports Apple's Time Machine capability. A note about Apple: For a street price of $470, you can get a Time Capsule with 2 TB of non-mirrored storage. Nice when your Mac's hard drive fails, but not so nice when the hard drive on the Time Capsule fails.
In line with Apple's general philosophy, the Time Capsule is designed to be dead simple and doesn't come cluttered with "unnecessary" features that you'll find on competing, less-expensive products. It just does one thing -- backup files -- and does it well. Although the company does offer the media-ready Apple TV and Mac Mini, Apple has yet to release a category-killer in NAS. We should expect them to try.
If the built-in capabilities of your operating system are insufficient, such as if you're using Windows Server or another server OS, one of these bundled options may appeal to you:
- Buffalo Technology TeraStation NAS devices include NovaBACKUP Business Essentials, which includes automatic backups, system imaging, and bare-metal restore with support for Windows Server, Microsoft Exchange, and SQL Server files.
- Iomega, an EMC company, includes EMC Retrospect Express with its StorCenter NAS devices.
- Seagate BlackArmor NAS devices enable discounts of over 20% on Acronis Backup & Recovery products.
Backing Up Your NAS Backup
Once you've successfully backed up every PC and device on your network onto the NAS, the natural progression will be the realization that someday, something bad could happen to your precious NAS. Here are some of the common approaches to backing up the backup device.
USB, eSATA, or Firewire connection: Most NAS devices come with at least one USB port, which you can use to connect an external hard drive. True, external hard drives are not RAID-enabled, but if you have one of those drives lying around, it can't hurt to make just one more copy, right? Your files will transfer even faster using either the eSATA or Firewire interface, if available.
NAS-to-cloud copy: The smart NAS providers realize that cloud storage is the perfect complement to home network storage as an extra layer of data assurance for your most important files. Leading the way in this area is Synology, which now includes server backup between its DiskStation NAS and an Amazon S3 server. While it may be relatively expensive to back up an entire NAS drive to Amazon S3 -- about $150 to upload 1 TB and $150 per month to keep it there -- you can cherry-pick your most important folders for synchronization with online storage. And the Amazon S3 pricing model undermines competing solutions, as with the Netgear ReadyNAS Vault, which charges $5.95 per month for 5 GB, or $199 annually for 50 GB.
Other Applications For NAS
So far, we've just talked about the core applications of storage and backup. But there are many other compelling reasons to deploy a NAS, and you may find that some devices are more suited than others to specific tasks.
UPnP and DLNA: These industry standards govern interoperability between home media devices, including the Xbox 360 and PlayStation 3. Most NAS devices support both standards, but it's worth checking your other audiovisual equipment against the certified product registries of the Digital Living Network Alliance and the UPnP Forum.
Print server: Let your NAS spool printer files by plugging a wired printer directly into an available USB port.
USB device offloading: Stop using your PC as a waystation for family pictures and other files by plugging your digital camera or other USB drive directly into the NAS. This is a common feature in NAS drives, and the more advanced models enable one-touch copying without having turn on the PC.
iTunes server: Many NAS devices permit you to create a "music" partition that can be shared by multiple users on a single network. However, these files are accessible through the shared library capability in iTunes, which does not support playlists. You can listen to whatever songs and albums you like, but you can't sync them to your portable MP3 player or set up your own playlists. For personal use, you're better off mapping the "music" partition as a virtual hard drive for direct indexing by the iTunes application.
Web server: You can set up your NAS as a home-based web server, accessible with a username and password from any computer or mobile device. Just make sure you've double- and triple-checked the security settings, assigned restrictive user privileges, used the more-secure HTTPS protocol if available, and don't blame me if you get hacked. Some approaches may give you greater comfort levels, such as having to login through the NAS provider's website, as with Buffalo Technology's BuffaloNAS.com for web access and native iPhone support for music and video streaming.
Surveillance cameras: You may be able to use your NAS to monitor wireless or IP-networked surveillance cameras. As an example, QNAP NAS devices support both audio and video feeds, with motion-detection and scheduling capabilities.
In the past, maintaining storage hygiene has been a dull chore. It's clearly a good idea to keep your files backed up, and now it's not only feasible to do so economically, but it can also form the core of a much more usable, functional, and capable network.
Here are some hard-earned words of wisdom that may help you on your search for the perfect NAS:
- Take a hard look at your data to come up with tiers of storage, ranging from "essential files that I'd want to take out of a burning house," to "I spent some money on this, but I wouldn't pay to replace it," to "why am I carrying these files around?" Your storage needs may vary significantly based on how you answer.
- On a NAS, 4.7 GB costs about $1.50 on an allocated basis. You can fit the same amount of data on a DVD-ROM costing $0.50. Don't buy a NAS for files that just need to be offloaded onto disk and put in a drawer somewhere.
- Estimate how much media you consume on a monthly or annual basis, and then adjust that figure upwards based on how excited you are about 3-D video and related innovations coming down the pike.
- Your budget should also take into account the potential for extending the useful life and functional capacity of your over-stuffed PCs.
- Come up with a "short list" of NAS devices based on compatibility with existing hardware and audiovisual equipment, cost, storage capacity, and those extra features most important to you.
- Once you've narrowed down the list based on your purchase criteria, read the manual (almost always available online). You'll be able to see what comes with the device, how easy it is to install and configure, and whether the features that look good on a checklist actually have the functionality you need.
- Tom's Hardware and HotHardware.com offer some pretty comprehensive hands-on reviews.
- Glance at the vendor-provided message boards to see how people are using the devices, what problems people generally have, and whether the support staff is on the job.
- Things can get tricky when you move NAS devices from one network to another. Keep good notes on network settings and the like.
- You don't really have a fully working backup until you've tried to restore your data.
For Further Reading