RAID, which is short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that makes it possible for a system to use several hard drives as one single logical unit. Simply put, all drives are used as one and the info on all of them is identical. This type of a setup has 2 huge advantages over using just a single drive to keep data - the first one is redundancy, so in case one drive stops working, the info will be accessible from the remaining ones, and the second is improved performance since the input/output, or reading/writing operations will be distributed among several drives. There're different RAID types based on how many drives are employed, whether reading and writing are both performed from all the drives concurrently, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, and so on. According to the particular setup, the fault tolerance and the performance vary.
RAID in Shared Web Hosting
The hard disks that we employ for storage with our revolutionary cloud hosting platform are not the standard HDDs, but quick NVMes. They work in RAID-Z - a special setup intended for the ZFS file system which we work with. Any content that you add to the shared web hosting account will be saved on multiple hard drives and at least 1 shall be employed as a parity disk. This is a specific drive where a further bit is added to any content copied on it. In case a disk in the RAID fails, it will be changed without service disruptions and the data will be rebuilt on the new drive by recalculating its bits thanks to the data on the parity disk plus that on the other disks. This is done in order to ensure the integrity of the data and together with the real-time checksum authentication which the ZFS file system executes on all drives, you won't ever have to be concerned about the loss of any information no matter what.