In the parts one and two of this series on using Linux in a small office, we covered what to look for in hardware and the operating system, security concerns, and choosing an Internet service provider. In this final installment, we'll talk about protecting the data on your hard drive. The hard drive is the single most likely point of failure in your computer, and the most critical component. While power supplies also frequently fail, modern journaled file systems will generally keep you from losing your data if this happens. If your machine has a single hard drive and nonexistent or insufficient backups, losing the hard drive may literally mean losing your business. A close relative of ours learned this the hard way. He ran a home office on a single hard drive machine with no reliable backup system. When the hard drive died, he lost two years' worth of work, and spent several thousand dollars on data recovery that took several weeks and was only partially successful. Using RAID can turn a hard drive failure from a business-ending catastrophe into a minor inconvenience.