NAS Buying Guide

Critical Decisions

Now that we've gone over the most important features, here are the decisions to make before you settle on an NAS model.

Storage capacity. How much space do you need? Drives come in a variety of sizes. A 1-terabyte (1TB) drive can store more than 300,000 digital photos, or 16,500 hours of digital music, or 250 DVD-quality movies. Here's a rule of thumb that can help you decide: Tally the amount of storage you presently consume and triple it to account for growth. As you can see from the numbers, video can eat up a lot of storage compared to other data formats, so plan accordingly.

Built-in drives vs. diskless. The most important part of any NAS is its disk storage, and you can purchase an NAS with built-in drives or buy them separately. D-Link offers both types of configuration, and there are tradeoffs either way. Built-in drives come pre-tested, guaranteed, and ready to use. There's nothing to configure. However, if you prefer a particular vendor's brand or would prefer to shop around, then diskless is the way to go. It's generally easier to replace a failed drive if you've purchased your own disks, as some NAS devices that include drives don't let you open the case and replace them (though this is not the case with D-Link's offerings). The D-Link ShareCenter page offers great information on how to pick compatible third-party disk drives.

Security. Consider how you'd like to share files among family or office workers. Do you need common storage areas that everyone can access? How about areas that are protected by passwords to prevent unauthorized access? All D-Link's NAS units can create both types of storage. You just need to plan accordingly.

Data value. In planning your storage needs, it's important to assess the value of the files you intend to store: Are they irreplaceable family photos? Are they critical to the daily operation of your business? Are they backups of your music CDs and videos you already own, or downloaded music that, in case of loss, you would have to repurchase? The more precious your data, the more critical it is that you have a backup system in place.

Data protection. Once you have a sense of how valuable your data is, then you'll know to what lengths you should go to protect it -- whether something low-key is just fine, or whether you need a really bomb-proof solution. Let's run down the options.

In the most basic setup, an NAS device can store data in a single volume on a single physical disk drive. D-Link refers to this arrangement as standard mode.

This setup might be fine for the Householder, but it won't work for the Office Manager -- it doesn't provide enough data security. After all, disk drives fail. To cover this possibility, many NAS devices house more than one drive, and multiple drives can be set up to store identical copies of your data. The good news is that this kind of protection used to cost thousands of dollars and required specialized knowledge, but with D-Link NAS products, a robust storage system is affordable and easy to set up.

To cover the possibility of drive failure, you need multiple drives set up in a configuration known as RAID, or redundant array of independent disks. RAID comes in different styles that are identified by number. For iron-clad data protection, the numbers are 1 and 5. It's important to remember that, while a NAS device might support multiple RAID numbers, once you settle on one, you can't easily change to another.

In RAID 1, which is supported by all D-Link NAS units, one drive mirrors another, storing the same data in two places. If one drive fails, there's a copy on the other. You give up half your total storage capacity, but in return you get rock-solid reliability. RAID 5 requires an NAS device with three or more drives, such as the DNS-343. Here, one drive is used for error checking. With four drives installed, you give up only 25 percent of the unit's storage capacity, but you gain a lot of protection.

The ideal setup is RAID protection along with an automated, scheduled backup that regularly duplicates your data.

Capacity and convenience

NAS lets you scale up storage capacity as you need it, for an increasingly larger collection of digital images, video, and other files. At home, a NAS unit can enhance your entertainment system and your small office, and the whole family can take advantage of it.

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