Yet RAID is not only about availability. Its other advantages are important and, for most, possibly more important.

• Performance. Striping data across multiple drives can dramatically increase bandwidth for large file apps like video editing.
• Capacity. Putting 4-12 drives in a RAID gives a large virtual disk that is much larger than any single drive.
• Management. After the often painful setup process - and until something breaks - RAID arrays are simpler to manage than individual disks. //

Many are still using small RAID5 arrays with 10^-14 error rates - me too! - and RAID5 seems to work fine. But adjustments should be made to account for the unchanged error rates.

• Always maintain a minimum of 2 copies any data stored on a RAID - 1 on the RAID and 1 elsewhere.
• Where there is a drive failure pull any unbacked up data - latest documents that aren't backed up - off the RAID before replacing the failed drive.

Since RAID arrays are more complex than individual drives, they are more likely to fail. But until they do they are more convenient, faster and larger than any single drive.