RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that enables a system to take advantage of many 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 type of a configuration has 2 key advantages over using a single drive to save data - the first one is redundancy, so in the event that one drive doesn't work, the information will be accessed from the others, and the second is better performance as the input/output, or reading/writing operations will be spread among a number of drives. There're different RAID types based on how many drives are used, whether reading and writing are both performed from all the drives at the same time, if data is written in blocks on one drive after another or is mirrored between drives in the same time, and so on. Determined by the particular setup, the fault tolerance and the performance vary.
RAID in Shared Hosting
The state-of-the-art cloud Internet hosting platform where all shared hosting accounts are created employs super fast SSD drives as an alternative to the classic HDDs, and they work in RAID-Z. With this setup, several hard disk drives function together and at least one is a dedicated parity disk. In simple terms, when data is written on the other drives, it's copied on the parity one adding an extra bit. This is performed for redundancy as even in case some drive fails or falls out of the RAID for whatever reason, the information can be rebuilt and verified thanks to the parity disk and the data saved on the other ones, so not a thing will be lost and there will not be any service interruptions. This is another level of protection for your information together with the state-of-the-art ZFS file system that uses checksums to guarantee that all of the data on our servers is intact and is not silently corrupted.