Data Storage Needs: Plan Before You Purchase

On the rare occasions when most of us think about data storage, it is merely to ponder how big a hard disk drive we'll need to cram in all our applications and data, or what size tape drive is enough for data backup. And when it comes time to make a pu rchase, the deciding factor is usually price (cost per megabyte). One element commonly overlooked -- and one especially important in a small office environment is: What are our precise data storage needs?

Storage needs

What storage medium is best suited to your office needs: hard disk, tape, CD-ROM, magneto-optical drive, or one of the several new technologies just coming on the market! While categorizing storage devices by media and technology is useful when making a purchase decision, the first step should be to consider potential use: What function(s) do you require for an optimum data storage solution? There are six basic functional categories of data storage devices.

A local storage device is one installed in your computer -- usually one from which you can boot. This is normally a hard disk (or, increasingly less frequently, a floppy disk).

An online storage device can be in your computer, but more commonly it is connected via a local area network (such as a CD-ROM drive, MO drive, or server-based hard disk). Like local storage, online storage offers near instantaneous access. Common wisd om holds that online network storage is most efficient for programs and data in an office setting. A network offers better data sharing, management, backup, and archiving solutions than local drives; with all critical data stored on a server, a network ad ministrator can back up the entire system automatically each night. If data is on local drives, responsibility for making backups rests with the individual users.

Near-online storage devices are those configured for large-volume storage that may take a few seconds to respond -- such as a CD-ROM jukebox or a tape changer. The main deciding factors for choosing between online or near-online storage are capacity an d frequency of data access. A jukebox or tape changer can provide relatively cheap extra capacity, but with a trade-off in access time.

Backup storage encompasses any media used to duplicate applications and data so that, if your primary storage device fails, you can recover. By enabling convenient backup of your entire local and/or online storage capacity with little or no operator in tervention, backup storage protects against loss of data for which you need regular access.

Archival storage is similar to backup storage, the main differences being that it need not hold the entire contents of your local and online capacity (usually, it is used lust for data backup) and is often not automatic. Archival storage is for data yo u will need infrequently, and for which you do not require quick access. Backup and archival storage can be (and often are) done with the same device.

And finally, distribution storage is a medium that allows data or programs to be interchanged between unconnected systems. The main criterion for choosing a distribution storage medium is that everyone needing to share the data must have equipment capa ble of reading it.

Making the choice

The criteria for choosing storage devices and media are both qualitative (throughput and access time) and quantitative (capacity and cost). There are trade-offs involved in any selection, but if you have adequately evaluated your needs, you should be a ble to select the most cost-effective and efficient solution for your office needs.

One question sure to arise is: "How much storage is enough?" The standard answer is: "You can never have too much." No matter how much capacity you buy, eventually you'll want more. A good rule of thumb is to calculate how much storage capacity your of fice needs now, then double it. If even that quickly proves too little, you can add more; and in the unlikely event it turns out to be too much, the price difference won't bankrupt you. The best bargains in data storage devices are usually one step back f rom the current "cutting edge" of the market (which will be "old technology" in six months or a year, anyway).

Ease of use and installation is an important consideration. Installing a hard drive is relatively easy; beyond that, things can get complicated. Seldom can you just go out, buy a storage drive, snap it into a computer, and expect it to work. You'll als o need a controller and driver software; these can have a dramatic impact on performance and flexibility, and need to be selected as carefully as the drive. Consider, too, how easy the storage system is to use. Even the best system will provide little ben efit if employees seldom use it because they find it too complicated, and stick to their local hard disk drive instead.

If you take the time to analyze and plan for your data storage needs now, you can save headaches and the chance of data loss later.