RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which permits a system to take advantage of a number of hard drives as a single logical unit. Simply put, all of the drives are used as one and the info on all of them is the same. This kind of a setup has 2 huge advantages over using a single drive to keep data - the first one is redundancy, so if one drive doesn't work, the data will be accessed from the remaining ones, and the second is improved performance since the input/output, or reading/writing operations will be distributed among multiple drives. You can find different RAID types based on what amount of drives are used, whether reading and writing are both executed from all of the drives at the same time, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, etc. According to the particular setup, the fault tolerance and the performance could differ.
RAID in Hosting
Our state-of-the-art cloud web hosting platform where all hosting accounts are created employs super fast SSD drives as an alternative to the traditional HDDs, and they operate in RAID-Z. With this configuration, numerous hard drives function together and at least one is a dedicated parity disk. Simply put, when data is written on the rest of the drives, it's cloned on the parity one adding an extra bit. This is done for redundancy as even in case a drive fails or falls out of the RAID for whatever reason, the info can be rebuilt and verified thanks to the parity disk and the data saved on the other ones, which means that practically nothing will be lost and there will not be any service interruptions. This is an additional level of security for your information in addition to the cutting-edge ZFS file system which uses checksums to guarantee that all the data on our servers is undamaged and is not silently corrupted.