A Redundant Array of Inexpensive Disks or RAID consists of two or more hard drives working together to provide data storage. While RAID arrays are typically associated with businesses, home computer users can benefit from the relatively high fault tolerance and fast response time that various types of RAID can provide.
These RAID levels are the most feasible options for home RAID implementation:
RAID 0 - A RAID 0 consists of an even number of drives. The RAID stripes data across drives equally. For example, if you wrote a single file to a two-drive RAID 0, half of the file would exist on either drive. This does not actually provide redundancy, and in this respect, RAID 0 is not a true RAID.
RAID 0 offers extremely fast performance, but no fault tolerance whatsoever. When a single drive fails, the RAID 0 will fail. Therefore, if you want a data storage device with fast access speeds and data loss is not a major concern, RAID 0 is a viable option. RAID 0 is useful for gaming, video streaming and other high-speed applications. However, if you want a way to protect your files from physical media failures, use another type of RAID.
RAID 1 - This RAID level consists of an even number of drives separated into two sets. The first set is mirrored onto the second set. Most home users set up RAID 1 with two drives, so every time a file is written to drive A, an exact copy is simultaneously written to drive B.
RAID 1 is not as fast as either of the other RAID levels mentioned in this article, but it provides excellent fault tolerance. If one drive fails, you can still access your data on the other drive. RAID 1 is also extremely easy to set up. Many hard drive manufacturers offer off-the-shelf RAID 1 systems for personal storage, and these devices are typically very affordable. If you decide to set up a two-drive RAID 1, you can expect to spend $200-500.
RAID 5 - RAID 5 consists of a minimum of three drives, but most implementations use at least four drives. The RAID's controller uses block-level striping to write to all of the disks at once, adding a special parity stripe that allows the controller to rebuild the array if a single hard drive fails. RAID 5 is faster than RAID 1, but not quite as fast as RAID 0, since the system has to write the parity stripe in addition to the data.
The major disadvantage of RAID 5 is that it requires a serious investment. You will also need some technical knowledge to maintain the system. If a drive fails, you need to exercise extreme caution when rebuilding the array to avoid data loss. Advanced users might prefer RAID 5 for data storage, but casual users should stick with RAID 1 or RAID 0.
These three RAID levels meet the needs of most home computer users. Other RAID options are overkill for personal data storage unless you work with extremely large amounts of data or if you need high availability.
Regardless of the storage option that you choose, remember that RAID is not a substitute for data backup in and of itself. Never store important files on a single physical device.
If you are not ready to invest in a RAID, consider cloud storage services as an alternative. Cloud services provide better fault tolerance than any of the RAID levels listed above, and most cost less than $10 a month for personal computer users.