Setting up a backup system is an essential task for any business, but it can also seem a complicated process as a full-proof system relies upon more than one technique. That way the weaknesses of one backup system can be offset by the complementary strengths of another.

A RAID (redundant array of independent or inexpensive drives) setup of internal hard drives can update a data backup in a split second. Unfortunately, it does not safeguard against the accidental deletion of data or the total destruction of a computer.

In this feature I'll look at backups that use removable storage media and discuss backup rotation and off-site storage.

Backups involving removable storage media are more time-consuming to perform than using RAID, taking up to several hours. However, daily backups can help recover accidentally deleted files that are more than a day old. And off-site storage of your backup media protects against a major disaster such as a fire, flood, or theft.

What's the best removable storage?

Let's consider the types of removable storage media available for your backup. Ideally, you want a relatively inexpensive form of data storage that is durable and reusable. It should have sufficiently high capacity to store all or most of your critical business data on one unit of media. The storage medium should be widely available and commonly used, so that the data on it can be quickly accessed and restored on another computer should the original PC be destroyed.

These requirements rule out some types of removable media fairly quickly. For example, while the floppy disk was once a favourite for backups, its limited storage capacity makes it virtually useless today. Most new PCs don't come with a floppy drive, so it's not even the universal portable storage solution it once was.

Optical discs

There was a time when I recommended CD-R media for backups. However, most businesses - except for one-man-bands or recently established firms - will have a greater quantity of important data than the 700MB or so that can be stored on a single CD.

Of course, you can spread a backup over multiple CDs, but shuffling discs in and out of drives isn't convenient, nor can it be easily automated using a standard CD drive.

Optical disc jukeboxes can shuffle 100 or so discs. But optical jukeboxes aren't cheap, and replacing discs for each new backup set could be time consuming.

Recordable DVDs - which provide 4.7GB of storage on single-layer discs, 9GB on dual-layer discs - can be a good solution for many small businesses. The discs are so inexpensive you needn't be concerned about reusing the media. (See an article on our US sister title PC World's site discussing archival-quality DVDs.)

The latest members of the optical media family - Blu-ray Discs and HD DVDs - can store even more data, up to 50GB per disc for Blu-ray and about 30GB for HD DVD. The blue-laser burners needed for these media are relatively expensive today, but will be more affordable in a year or two.