RAID, which is short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which makes it possible for a system to take advantage of multiple hard drives as a single logical unit. Put simply, all drives are used as one and the info on all of them is the same. This kind of a configuration has 2 huge advantages over using just a single drive to store data - the first is redundancy, so if one drive doesn't work, the information will be accessed from the others, and the second is better performance since the input/output, or reading/writing operations will be spread among a number of drives. There're different RAID types based on what amount of drives are used, if reading and writing are both executed from all of the drives concurrently, if data is written in blocks on one drive after another or is mirrored between drives in the same time, and many others. Depending on the particular setup, the fault tolerance and the performance could differ.
RAID in Shared Hosting
Our cutting-edge cloud Internet hosting platform where all shared hosting accounts are generated uses fast SSD drives as opposed to the standard HDDs, and they work in RAID-Z. With this setup, a number of hard disk drives operate together and at least one is a dedicated parity disk. Basically, when data is written on the other drives, it's duplicated on the parity one adding an extra bit. This is performed for redundancy as even if a drive fails or falls out of the RAID for some reason, the info can be rebuilt and verified using the parity disk and the data recorded on the other ones, which means that not a thing will be lost and there will not be any service disturbances. This is another level of security for your info along with the revolutionary ZFS file system which uses checksums to make sure that all the data on our servers is undamaged and is not silently corrupted.