It's (a) RAID!
Don't be concerned - this is RAID you want.
If your data is vital, if you need to have access to it all the time, if your work will suffer if you lost it, then you want RAID, specifically HC-RAID.
First, let's explain what a hard disk is, how it works and why you should care. The hard disk is the place your data is saved. Today's hard disks are fast and have high storage capacity. These features are great, but they come at a high price. That price is dependability. Hard disks are not dependable since they are extremely fragile.
This next part gets technical, but it's great information. Hard disks are generally glass or ceramic platters mounted vertically, thinly coated with magnetically sensitive material and incased in a hard drive. Data on the disk is read and written by magnets suspended by an arm above and/or below the platters. This magnet works with microscopic sections of the disks. As the arm needs to fit in between the platters which are mounted very close together, the arm is extremely thin which makes it flexible. The flexible arm needs to be very very very close to the platter so that the magnet can read and write to/from these microscopic areas. The magnet is so close to the platter that even a very gentle movement can cause the magnet to scratch it: a house moving in the wind or sliding the computer across a desk while it's turned on. If the hard disk is touched, it will be damaged. A damaged disk will get progressively worse over time, until the computer just stops booting and all data is lost. The hard disk is the most critical part of the computer, since that's where your data is stored, yet it's the most fragile.
But you can protect your data and it's easy to do. Many computers today are available with HC-RAID: Hardware Controlled Redundant Array of Inexpensive Disks. A computer with HC-RAID saves all data to an HC-RAID controller, a mini computer inside the main computer, which saves the data to multiple hard drives simultaneously. The HC-RAID controller monitors the disks constantly and when damage is detected or a hard drive fails, the HC-RAID controller stops the drive, switching all activity to the working drive -- all while the computer is on, without any help from you. You keep on working without interruption or data loss. The damaged drive can then be replaced. Many computers with HC-RAID are designed to allow the hard drives to be replaced without taking apart or shutting down the computer.
If you decide to go for a new computer with HC-RAID, be sure the computer has at least 128MB cache, a 3 day internal cache battery, and that the configuration uses the hard drives in an array type other than RAID 0.
If this sounds exciting, it is! No data loss. No downtime. And it's readily available. Your data can be totally safe!