Redundant Array of Independent Disks, or RAID, is a way of storing content on several hard drives at the same time. A RAID might be software or hardware depending on the HDDs which are used - physical or logical ones, however what is common between them is that they all work as just a single unit where data is saved. The main advantage of employing a RAID is redundancy since the data on all of the drives is exactly the same all of the time, so even in the event that one of the drives fails for some reason, the data will still be available on the rest of the drives. The overall performance is enhanced as well since the reading and writing processes will be split between a number of drives, so a single one can't be overloaded. There are different kinds of RAIDs where the functionality and fault tolerance could differ depending on the particular setup - whether info is written on all of the drives in real time or it is written on one drive and after that mirrored on another, the number of drives are used for the RAID, and many others.
RAID in Cloud Hosting
The cutting-edge cloud web hosting platform where all cloud hosting accounts are made employs fast SSD drives rather than the traditional HDDs, and they operate in RAID-Z. With this setup, numerous hard drives operate together and at least 1 is a dedicated parity disk. Basically, 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 in case some 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 saved on the other ones, therefore nothing will be lost and there won't be any service disturbances. This is another level of security for your info along with the state-of-the-art ZFS file system which uses checksums to ensure that all data on our servers is intact and is not silently corrupted.