Redundant Array of Independent Disks, or RAID, is a method of saving content on multiple hard drives concurrently. A RAID might be software or hardware based on the hard drives which are used - physical or logical ones, still what is common between them is the fact that they all operate as a single unit where your information is kept. The main advantage of employing a RAID is redundancy because the data on all of the drives is exactly the same at all times, so even if a drive fails for whatever reason, the data will still be present on the other drives. The overall performance will also improve because the reading and writing processes will be split between different drives, so a single one can't be overloaded. There're different sorts of RAIDs where the performance and fault tolerance can vary according to the specific setup - whether info is written on all the drives in real time or it is written on a single drive and after that mirrored on another, what number of drives are used for the RAID, and many others.
RAID in Shared Web Hosting
The hard drives that we employ for storage with our revolutionary cloud web hosting platform are not the classic HDDs, but high-speed solid-state drives (SSD). They work in RAID-Z - a special setup developed for the ZFS file system that we work with. All of the content that you add to your shared web hosting account will be kept on multiple hard disks and at least one of them will be employed as a parity disk. This is a specific drive where an extra bit is added to any content copied on it. If a disk in the RAID stops working, it will be replaced with no service interruptions and the information will be recovered on the new drive by recalculating its bits using the data on the parity disk plus that on the remaining disks. This is done in order to ensure the integrity of the info and along with the real-time checksum verification that the ZFS file system executes on all drives, you'll never need to be concerned about the loss of any info no matter what.