Redundant Array of Independent Disks, or RAID, is a way of storing content on multiple hard disk drives simultaneously. A RAID can be software or hardware depending on the HDDs which are used - physical or logical ones, yet what’s common between them is the fact that they all function as one single unit where data is saved. The biggest advantage of employing a RAID is redundancy as the data on all the drives is exactly the same at all times, so even in case some drive fails for some reason, the information will still be available on the rest of the drives. The overall performance is also enhanced since the reading and writing processes will be split between various drives, so a single one can't be overloaded. There are different sorts of RAIDs where the functionality and fault tolerance can vary based on the exact setup - whether data is written on all of the drives in real time or it's written on one drive and afterwards mirrored on another, what number of drives are used for the RAID, etc.
RAID in Hosting
The advanced cloud Internet hosting platform where all hosting accounts are made employs quick SSD drives rather than the traditional HDDs, and they work in RAID-Z. With this setup, numerous hard drives function together and at least one is a dedicated parity disk. Put simply, when data is written on the other drives, it's duplicated 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 whatever reason, the information can be rebuilt and verified using the parity disk and the data saved on the other ones, therefore not a single thing will be lost and there will be no service disturbances. This is another level of protection for your data in addition to the advanced ZFS file system which uses checksums to ensure that all of the data on our servers is undamaged and is not silently corrupted.