Redundant Array of Independent Disks, or RAID, is a method of storing content on a number of hard disks simultaneously. A RAID can be software or hardware based on the hard drives which are used - physical or logical ones, yet what is common between them is that they all function as just one single unit where data is stored. The biggest advantage of employing a RAID is redundancy because the information on all of the drives is identical all the time, so even if a drive fails for whatever reason, the data will still be available on the remaining drives. The overall performance is also enhanced as the reading and writing processes will be split between multiple drives, so a single one will never be overloaded. There're different sorts of RAIDs where the functionality and fault tolerance may differ based on the exact setup - whether your data is written on all the drives real-time or it is written on a single drive and then mirrored on another, what amount of drives are used for the RAID, etc.
RAID in Shared Website Hosting
The hard drives which we employ for storage with our innovative cloud Internet hosting platform are not the traditional HDDs, but fast solid-state drives (SSD). They function in RAID-Z - a special setup created for the ZFS file system which we work with. Any content that you add to the shared website hosting account will be held on multiple disk drives and at least one of them shall be employed as a parity disk. This is a specific drive where an additional bit is included to any content copied on it. In the event that a disk in the RAID stops working, it will be replaced with no service disruptions and the information will be recovered on the new drive by recalculating its bits using the data on the parity disk along with that on the other disks. This is done in order to guarantee the integrity of the information and together with the real-time checksum validation which the ZFS file system executes on all drives, you won't ever need to be concerned about losing any data no matter what.