Redundant Array of Independent Disks, or RAID, is a way of keeping content on several hard drives at the same time. A RAID might be software or hardware depending on the hard drives that are used - physical or logical ones, still what’s common between them is the fact that they all perform as a single unit where information is stored. The main advantage of employing a RAID is redundancy because the data on all drives will be exactly the same all of the time, so even in case some drive fails for whatever reason, the data will still be present on the remaining drives. The general performance is also better as the reading and writing processes could be split between multiple drives, so a single one will never be overloaded. There're different sorts of RAIDs where the performance and fault tolerance may differ depending on the particular setup - whether info is written on all drives real-time or it is written on one drive and then mirrored on another, what amount of drives are used for the RAID, etcetera.
RAID in Website Hosting
The hard disks that we use for storage with our ground-breaking cloud web hosting platform are not the traditional HDDs, but high-speed solid-state drives (SSD). They function in RAID-Z - a special setup developed for the ZFS file system that we work with. Any content that you upload to the website hosting account will be stored on multiple hard disks and at least one will be used as a parity disk. This is a specific drive where a further bit is added to any content copied on it. In the event that a disk in the RAID stops functioning, it will be replaced with no service disruptions and the data will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk plus that on the other disks. This is done to guarantee the integrity of the information and together with the real-time checksum verification which the ZFS file system runs on all drives, you will never have to worry about the loss of any data no matter what.