RAID is the linking together of two hard drives, either for increased performance (RAID 0) or for increased security (RAID 1).
RAID 0: STRIPE
RAID level 0 refers to striping data across multiple disks without any redundant information. Striping can be used to enhance performance in either a request rate intensive or transfer rate intensive environment. Unfortunately. Striping reduces the level of data availability since a disk failure will cause the entire array to be inaccessible.
1. Higher performance.
2. No cost penalty - all storage is usable.
Significantly reduced data availability - all data is lost if one hard drive fails.
RAID 1: MIRROR
RAID level 1 refers to maintaining duplicate sets of all data on separate disk drives. Of the RAID levels, level 1 provides the highest data availability since two complete copies of all information are maintained. If one of your hard drives fails, you will have an exact copy of all your data on your other hard drive, meaning that you can carry on working as normal without having to restore lost files. You could see it as having a permanent automatic back-up of all your data. Even if one hard drive fails, you can then use the other hard drive to create a new RAID array and so in theory (unless you have an electrical surge, or both hard drives fail simultaneously) you can never be caught out when you turn on your computer one day to find that your hard drive has failed, because you always have a backup.
1. Excellent data availability.
2. Higher read performance than a single disk.
1. Expensive - requires two hard drives (if you order 2 x 500GB, you will only have 500GB total storage space and not 1000GB).
For some customers such as business users, RAID 1 can be a very cost effective way of backing up their data to protect against single hard drive failure. For enthusiasts, RAID 0 will increase the read/write speeds of data on your computer to give you a little extra performance.
However, for the average home computer, most customers prefer not to order a RAID configuration because they do not want to limit their data capacity on ordering two hard drives, nor do they want the increased risk of data loss should a single hard drive fail.
When choosing a RAID 1 configuration with a view to data security, we always recommend you continue to perform separate backups, and do not solely rely on the RAID configuration as your data backup.