Storage buying guide

Information runs the computing world, and handling it is crucial. So it's important that you select the best storage device to not only keep your data, but also distribute it. In this guide, I'll explain the basics of storage and list the features that you should consider when shopping. But if you're ready to leave for the store right now, here are my top picks.

Hard-core users hoping to get the most out of a home storage solution should consider a network-attached storage (NAS) server from Synology, such as the DS1511+, DS412+, or the DS213air. Both offer superfast speeds, a vast amount of features, and state-of-the-art user interfaces and are more than worth the investment.

Alternatively, if you want to make your computer faster, a solid-state drive (SSD) such as the Samsung 830, the Intel 520, or the OCZ Vertex 4 will significantly boost speeds of your current hard-drive-based system.

Do you have information that you just can't afford to lose? Then I'd recommend the heavyweight, disaster-proof IoSafe Solo G3. You can't damage this drive even if you try. However, if you just want to casually extend your laptop's storage space, a nice and affordable portable drive, such as the Seagate Backup Plus, the WD My Passport, or the Buffalo MiniStation Thunderbolt will do the trick.

Now if you want to know more about storage, I invite you to read on. On the whole, there are three main points you should consider when making your list: performance, capacity, and data safety. I'll explain them briefly here. And after you're finished, check out this related post for an even deeper dive into the world of storage.

Using an SSD like one of these will greatly improve your computer's performance.

(Credit: Dong Ngo/CNET)

Performance

Storage performance refers to the speed at which data transfers within a device or from one device to another. Currently, the speed of a single consumer-grade internal drive is defined by the Serial ATA (SATA) interface standard, which determines how fast internal drives connect to a host (such as a personal computer or a server), or to one another. There are three generations of SATA, with the latest, SATA 3, capping at 6Gbps (or some 770MBps). The earlier SATA 1 and SATA 2 versions cap data speeds at 1.5Gbps and 3Gbps, respectively.

So what do those data speeds mean in the real world? Well, consider that at top speed, an SATA 3 drive can transfer a CD's worth of data (about 700MB) in less than one second. The actual speed may be slower due to mechanical limitations and overheads, but you get the idea of what's possible. Solid-state drives (SSDs), on the other hand, offer speeds much closer to the top speed of the SATA standard. Most existing internal drives and host devices (such as computers) now support SATA 3, and are backward-compatible with previous revisions of SATA.

Since internal drives are used in most other types of storage devices, including external drives and network storage, the SATA standard is the common denominator of storage performance. In other words, a single-volume storage solution -- one that has only one internal drive on the inside -- can be as fast as 6Gbps. In multiple-volume solutions, there are techniques that aggregate the speed of each individual drive into a faster combined data speed, but I'll discuss that in more detail below.

Capacity

Capacity is the amount of data that a storage device can handle. Generally, we measure the total capacity of a drive or a storage solution in gigabytes (GB). On average, one GB can hold about 500 iPhone 4 photos, or about 200 iTunes digital songs.

Currently, the highest-capacity 3.5-inch (desktop) internal hard drive can hold up to 4 terabytes (TB) or 4,000GB. On laptops, the top hard drive has up to 2TB of space and solid-state drive (SSD) can store up to 512GB before getting too expensive to be practical.

While a single-volume storage solution's capacity will max out at some point, there are techniques to combine several drives together to offer dozens of TB, and even more. I'll discuss that in more detail below.

Having a layer of protection, like this LaCie Rugged drive has, helps keep the internal drive inside from being damaged by shocks and drops.

(Credit: Dong Ngo/CNET)

Data safety

Data safety depends on the durability of the drive. And for single drives, you also have to consider both the drive's quality and how you'll use it.

Generally, hard drives are more susceptible to shocks, vibration, heat, and moisture than SSDs. For your desktop, durability isn't a big issue since you won't move your computer very often. For a laptop, however, I'd recommend an SSD or a hard drive that's designed to withstand shocks and sudden movements.

For portable drives, you can opt for a product that comes with layers of physical protection, such as the LaCie Rugged Thunderbolt, the IoSafe Rugged Portable, or the Silicon Power Armor A80. These drives are generally great for those working in rough environments.

But even when you've chosen the optimal drive for your needs, don't forget to use backup, redundancy, or both. Even the best drive is not designed to last forever, and there's no guarantee against failure, loss, or theft.

The easiest way to back up your drive is to regularly put copies of data on multiple storage devices. Many external drives come included with automatic backup software for Windows. Macs users, on the other hand, can take advantage of Apple's Time Machine feature. Note that all external drives work with both Windows and Macs, as long as they are formatted in the right file system: NTFS for Windows or HFS+ for Macs. The reformatting takes just a few seconds. For those who are on a budget, here's the list of top five budget portable drives.

Yet, this process isn't foolproof. Besides taking time, backing up your drive can leave small windows in which data may be lost. That's why for professional and real-time data protection, you should consider redundancy.

RAID

The most common solution for data redundancy is RAID, which stands for redundant array of independent disks. RAID requires that you use two internal drives or more, but depending on the setup, a RAID configuration can offer faster speeds, more storage space, or both. Just note that you'll need to use drives of the same capacity. Here are the three most common RAID setups.

RAID 1
Also called mirroring, RAID 1 requires at least two internal drive drives. In this setup, data writes identically to both drives simultaneously, resulting in a mirrored set. What's more, a RAID 1 setup continues to operate safely even if only one drive is functioning (thus allowing you to replace a failed drive on the fly). The drawback of RAID 1 is that no matter how many drives you use, you get the capacity of only one. RAID 1 also suffers from slower writing speeds.

RAID 0
Like RAID 1, RAID 0 requires at least two internal drives. Unlike RAID 1, however, RAID 0 combines the capacity of each drive into a single volume while delivering maximum bandwidth. The only catch is that if one drive dies, you lose information on all devices. So while more drives in a RAID 0 setup means higher bandwidth and capacity, there's also a greater risk of data loss. Generally, RAID 0 is used mostly for dual-drive storage solutions. And should you chose RAID 0, backup is a must.

For a storage device that uses four internal drives, you can use a RAID 10 setup, which is the combination of RAID 1 and RAID 0, for both performance and data safety.

RAID 5
This setup requires at least three internal drives, but it distributes data on all drives. Though a single drive failure won't result in the loss of any data, performance will suffer until you replace the broken device. Still, because it balances storage space (you lose the capacity of only one drive in the RAID), performance, and data safety, RAID 5 is the preferred setup.

Most RAID-capable storage devices come with the RAID setup preconfigured; you don't need to configure the RAID setup yourself.

Now that you've learned how to balance performance, capacity, and data safety, let's consider the three main types of storage devices: internal drives, external drives, and network-attached storage (NAS) servers.

A typical 2.5-inch (laptop) and a 3.5-inch (desktop) SATA internal hard drive.

(Credit: Dong Ngo/CNET)

Internal drives

Though they share the same standard the same SATA interface, the performance of internal drives can vary sharply. Generally, hard drives are much slower than SSDs, but SSDs are much more expensive than hard drives, gigabyte-to-gigabyte.

That said, if you're looking to upgrade your system's main drive (the one that hosts the operating system), it's best to get an SSD. You can get an SSD with a capacity of 256GB or less (currently cost some $200 or less), which is enough for a host drive. You can always add more storage via an external drive, or in the case of a desktop, another regular secondary hard drive.

Though not all SSDs offer the same performance, the differences are minimal. To make it easier for you to choose, here's the list of current best five internal drives.

Thunderbolt is currently the faster peripheral connection for external drives.

(Credit: Dong Ngo/CNET)

External drives

External storage devices are basically one or more internal drives put together inside an enclosure and connected to a computer using a peripheral connection.

There are four main peripheral connection types: USB, Thunderbolt, FireWire, and eSATA. Most, if not all, new external drives now use just USB 3.0 or Thunderbolt or both. There are good reasons why.

USB 3.0 offers the cap speed of 5Gbps and is backward-compatible with USB 2.0. Thunderbolt caps at 10Gbps, and you can daisy chain up to six Thunderbolt drives together without degrading the bandwidth. Thunderbolt also allows for RAID when you connect multiple single-volume drives of the same capacity. Note that there are more computers that support USB 3.0 than Thunderbolt, especially among Windows computers. All existing computers support USB 2.0, which also works with USB 3.0 drives (though at USB 2.0 data speed).

Generally, speed is not the most important factor for non-Thunderbolt external drives. That may seem counterintuitive, but the reason is that the USB 3.0 connectivity standard, which is the fastest among all non-Thunderbolt solutions, is slower than the speed of SATA 3 internal drives.

Capacity, however, is a bigger issue. USB external drives are the most affordable external storage devices on the market and they come with a wide range of capacities to fit your budget. Make sure you get a drive that offers at least the same capacity as your computer. Check out the list of best five external drives for more information.

Currently, Thunderbolt storage devices are more popular for Macs and, unlike other external drives, deliver very fast performance. Yet, they are significantly more expensive than USB 3.0 drives, with prices fluctuating a great deal depending on the number of internal drives you use. Here's the top five Thunderbolt drives on the market.

The five-bay Synology DS1511+ is one of the best NAS servers on the market.

(Credit: Dong Ngo/CNET)

Network-attached storage (NAS) devices

A NAS device (aka NAS server) is very similar to an external drive. Yet, instead of connecting to a computer directly, it connects to a network via a network cable (or Wi-Fi) and offers storage space to the entire network at the same time.

As you might imagine, NAS servers are ideal for sharing a large amount of data between computers. Besides storage, NAS servers offer many more features, including (but not limited to) the ability to stream digital content to network players, downloading files on its own, back up files from network computer, sharing data over the Internet, and much more.

If you're in the market for an NAS server, note that its data rate is capped to that of a Gigabit network connection, which is about 130MBps at most -- far less than the speed of the internal drives themselves. That said, you should focus on the capacities of the internal drives used. Also, it's a good idea to get hard drives that use less energy and are designed to work 24-7 since NAS servers are generally left on all the time. Go to the list of best five NAS servers to see my top list.

Happy shopping!