RAID, which stands short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that enables a system to use many hard drives as one single logical unit. Put simply, all the drives are used as one and the data on all of them is the same. This kind of a setup has 2 huge advantages over using a single drive to store data - the first is redundancy, so in case one drive stops working, the data will be accessible from the others, and the second one is better performance since the input/output, or reading/writing operations will be spread among a number of drives. There're different RAID types in accordance with how many drives are used, if reading and writing are both executed from all 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. According to the particular setup, the error tolerance and the performance could differ.
RAID in Hosting
The revolutionary cloud hosting platform where all hosting accounts are created uses super fast SSD drives instead of the classic HDDs, and they work in RAID-Z. With this setup, multiple hard disk drives work together and at least one of them is a dedicated parity disk. Put simply, when data is written on the remaining drives, it is copied 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 some reason, the data can be rebuilt and verified thanks to the parity disk and the data stored on the other ones, therefore not a single thing will be lost and there will not be any service interruptions. This is another level of protection for your info 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.