Multiple Hard Drive Failures in a RAID

RAID can be a very helpful tool, especially for small businesses. It is however, due to its complex nature, not recommended for the average individual. RAID is an acronym that stands for “Redundant Array of Independent Disks” or “Redundant Array of Inexpensive Disks.” This array of disks can be set up multiple ways: RAID 0, RAID 1, RAID 5, etc.  Each one of these disk arrays has a specific purpose that it is use for, and each comes with its own advantages and disadvantages.


RAID 0 is chosen because it speeds up overall performance of data storage. This version of RAID takes the user’s data and distributes it among the collection of linked drives. It doesn't make multiple copies or mirror the data. This system just spreads the data out on separate disks to increase speed. It isn’t recommend for critical data because it offers no protection for your data if your drive fails. The data recovery process would be the same for the drives, but the array set up would be different from a plain master hard drive.


RAID 1 is used because of its mirroring capabilities. RAID 1, like RAID 0, requires at least two disks. When using RAID 1, your computer writes the data to both disks, like writing on carbon paper. This process is called mirroring, and it ensures you always have two exact copies of your data at all times. If one fails you can use the second copy as if nothing has gone wrong. The failed drive can be replaced in short order with no long-lasting, negative effects. The key to this kind of RAID is having replacement drives nearby to replace the failed ones. If both drives fail, you’re out of luck, and will have to get the data extracted off of one or both of them. If it is a logical failure they will be equally bad in recovery, because the read/write data was the same to each of them. If they both experienced a physical failure, the identical drive with the least damage will be used first for recovery. It is essential that if one drive fails, the user replaces it and brings it up to speed with the other one, just in case drive two also fails. This type of RAID is not infallible because on occasion the good drive can mirror the damage from the failed drive and still cause a data loss problem.


RAID 5 is the most widely used but has a more complicated redundant drive system. It uses a minimum of three drives. It combines the advantages of RAID 0 and RAID 1. It is both fast and protective with you data. Your machine reads and writes on all of the disks seamlessly. This array uses parity distributed between the disks. This allows a small amount of data to represent a large amount of data through mathematic derivation. This means the small amount can restore the large amount when needed. Since each drive has parity working on it, one of them could fail and the rest of the array would make up for it. Each failed drive would have to be replaced, but the array functions so that all the data will not be lost with an individual or multiple drive failure.