How to Buy Network-Attached Storage Drives

Almost every small business can benefit from some form of network-attached storage, or NAS. NAS drives are essentially intelligent hard drives that connect directly to your local area network, rather than to a PC or server. Common uses are central file storage, media streaming, print serving and backup for all the local drives on your network. You can even access most NAS drives from the Internet if desired.

The NAS spectrum covers a wide range of products, from simple boxes with a fixed amount of storage that you can plug into your network (basically glorified hard drives) all the way up to full-fledged network storage appliances with features like hot-swappable RAID arrays, flexible and secure account management, remote FTP and HTTP access, print serving and more.

Just don't call them "servers," a term generally reserved for full computers with operating systems (typically Windows Server or Linux) able to run programs like database and Web applications, as well as store large amounts of data. NAS drives, by contrast, have purposely limited functionality, embedded processors, and hardened "kernel" operating systems. Because of their very limitations, such as the inability to install and run most third-party applications, NAS drives can also be more secure than PC-based file servers.

NAS or Server?

Assuming you need centralized storage, whether to choose a NAS device or a file server will hinge on several factors:

  • Your Budget. NAS devices are much cheaper than file servers, and also don't require their own monitors and keyboards since they are managed via a Web interface over your network.
  • IT Administration Resources. NAS devices require far less administration than servers. After initial configuration and setup, you generally only need to make occasional user and account updates. File servers require active administration to keep system patches, virus definitions and application software up to date, among other things.
  • Application Demands. The need to run applications like groupware or e-mail and Web servers--all of which require the horsepower of a file server.
  • The Number of Users. File servers can usually be scaled up much higher than NAS devices, which typically accommodate a maximum of about 25 simultaneous users.
  • Performance. While the raw determinants of network storage performance will be connection and hard drive speeds for either type of storage, the faster processors and optimized hardware in file servers give them an edge over NAS for mission-critical and real-time applications.

Many businesses use a mix of NAS and server hardware. They might have a NAS drive dedicated to backup and print serving, as well as a file server handling a central company database and other shared files. Backup is definitely the number one use of NAS by small businesses.

Features to Look For

So what should you look for in a NAS device? That depends on what you will be doing with it, and how secure it needs to be. Here's a rundown of features:

Drive Type and Configuration. The essence of any NAS is storage, and the first thing to figure out is how much disk space you need. For backup, add up the sizes of your employees' hard drives--and then factor in some extra capacity. While you'll typically only back up a fraction of that space, the extra overhead will allow room to grow, as well as leave plenty of room for multiple versions of files. For central document and media libraries, again, determine how large your data set is, and allow room to grow. If you expect your needs to increase dramatically over the life of the NAS (about three to five years), consider a user-replaceable, multidrive expandable solution, so you can add to it later as required. Drive prices drop dramatically over time, so this approach will also save you money.

How much capacity you'll want will depend in part on whether you want your NAS in a RAID configuration (which can require up to twice as much space). If you have a two-drive setup, you can use RAID 1, which simply mirrors one drive onto the other in real time (and reduces total storage capacity by half, so make sure the NAS offers double your basic capacity requirements).

For multidrive setups, we recommend RAID 5, which stripes data across a minimum of three drives (increasing performance), while at the same time allowing for complete recovery in the event of a single drive failure. Many multidrive NAS enclosures allow you to hot-swap drives: You can pop out and replace a failed drive without even turning off the NAS. For RAID 5, you'll need about 50 percent more capacity than you expect to back up (assuming a three-drive array), or about one-third more if you have a four-drive array. This translates into a less costly setup than with RAID 1. Another point to note: Multiple smaller drives are usually a cheaper route than buying one or two big drives.

Stay away from RAID 0; striping data across the capacity two drives may increase your performance, but it also increases the risk to your data should one of those drives fail.

(Note that while RAID can guard against individual drive failure, it can't protect against corruption that may spread to all drives; NAS system failure; or a catastrophe like a fire, flood, or earthquake that may destroy both your local computers and the NAS. We recommend you continue to perform regular backups onto removable media that can be taken offsite or to an online backup service.)

Finally, you'll want to ask if the drives in your NAS will be regular or "enterprise-class." Enterprise-class drives are carry a much higher mean time between failures (MTBF) than do standard consumer drives, and as such are more reliable. You can often choose one or the other drive type. The price premium for enterprise-class hardware is small and can be well worth it for businesses. If you do have the chance to pick your drives, we recommend choosing 7200rpm or 10,000rpm enterprise-class drives over 7200rpm standard drives. You will likely be striping the drives in an array (which can double performance) at any rate, so we suggest going for reliability, which is generally a more important factor than pure drive speed for NAS.

Network Connections and Performance. Definitely look for gigabit Ethernet connections in any office NAS, and make sure you have gigabit routers and switches. Backups involve moving large amounts of data over the network, and can take hours and hours on slow connections (especially wireless ones). Also try to stagger user backups throughout the week, and perform them at night, so they don't affect your network operations during the business day.

Ease of Setup and Installation. Most NAS devices have Web-based configuration utilities that let you set up user and group accounts, create drive "shares" and public folders, allow remote Web access via FTP or HTTP, format the drive, update firmware, set your Workgroup name, and so on. Some have wizards that take you through the process, making it easy for a part-time system administrator to get started. Access-rights management will be the key ongoing administrative task. Make sure that you can assign secure private shares using passwords and/or encryption, and provide read-only access to specific shares and users if needed. Most units offer a built-in print server, and even have additional USB 2.0 ports for attaching a flash drive or hard drive.

Bundled Software. Look for models that include backup utilities with the power and flexibility to meet your needs, or the capability to work with third-party backup apps. Most NAS drives can be used with popular software like EMC Dantz's Retrospect; some models even come with multi-seat Retrospect licenses. Other embedded utilities may include defragmentation tools, formatting, and virus scanning software.

Management & Logging Tools. The last thing a busy small business administrator needs is the hassle of frequently checking to see whether backups were performed correctly, whether users are nearing the limits of their disk space allocations, and other such maintenance tasks. The best NAS devices will alert you to issues like almost full disks or shares, failed backups, fragmented drives and attempts at unauthorized access so you can correct them before they cause problems. Good logs of disk and system activity will also help you diagnose issues.

Security. NAS devices in general are more secure than file servers that can run third-party software (and by extension, malware). However, you probably don't want to place trade secrets on any shared storage drive, especially one that might be available on the Web. The most secure NAS devices will have strong access-rights management, with password-protected accounts, groups and shares, and division of rights by read, write and read/write access. They will also have clear instructions that help you set things up securely--most NAS security problems are created simply by bad rights setup. Grant read/write access only to share owners, and grant group access only to folders clearly labeled as such. For backup of personal drives onto a NAS, use software that allows you to encrypt the backup. That way, snoopers cannot read it even if they somehow gain access to it.

File Protocol Support. If you have Mac or Linux machines on your network as well as PCs, a key consideration will be network file protocol support. Most NAS devices support at least Server Message Block/Common Internet File System (SMB/CIFS) and Network File System (NFS). SMB/CIFS is used most commonly on Windows systems for file sharing, while NFS is more popular on Unix systems, but both can be accessed by PC, Mac, and Linux clients. However, Mac users especially may have problems with the file conventions allowed by these non-Mac-native protocols. If you have more than a few Mac clients, look for a NAS with Apple Filing Protocol (AFP) support. Many NAS devices support AFP on Mac shares, along with SMB/CFS on PC shares.

Remote Web Access. Not all NAS devices allow remote FTP and HTTP access, so make sure yours has this feature if you need it. Also make sure you harden the passwords and security on shares of the NAS that will not be granted remote access. You don't want your NAS to end up being a "back door" into your network.

Warranty/Support. The warranty on both drives and NAS hardware and the ease of obtaining technical support are crucial factors for many small businesses. Basic warranties range from one to three years, and some vendors offer extended on-site service at extra cost. Drives are often separately guaranteed by the drive manufacturer, however, unless they're integrated into the NAS, so be sure to ask for warranty information on both. Avoid tech support that is unavailable outside of business hours, and any that is available for only a limited time after purchase.

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