RAID, which stands short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that makes it possible for a system to take advantage of multiple hard drives as a single logical unit. To put it differently, all drives are used as one and the data on all of them is identical. Such a setup has 2 major advantages over using just a single drive to keep data - the first one is redundancy, so if one drive fails, the data will be accessed from the remaining ones, and the second is better performance as the input/output, or reading/writing operations will be distributed among several drives. You can find different RAID types based on how many drives are employed, whether reading and writing are both executed from all the drives simultaneously, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, etcetera. Determined by the exact setup, the fault tolerance and the performance could differ.
RAID in Web Hosting
The advanced cloud web hosting platform where all web hosting accounts are generated employs fast SSD drives as opposed to the standard HDDs, and they function in RAID-Z. With this setup, several hard disk drives function together and at least a single one is a dedicated parity disk. Put simply, when data is written on the remaining drives, it is cloned on the parity one adding an extra bit. This is carried out for redundancy as even if some 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 recorded on the other ones, so not a single thing will be lost and there won't be any service interruptions. This is another level of protection for your data in addition to the state-of-the-art ZFS file system that uses checksums to make sure that all the data on our servers is intact and is not silently corrupted.