Redundant Array of Independent Disks, or RAID, is a method of keeping content on several hard drives at the same time. A RAID could be software or hardware depending on the HDDs which are used - physical or logical ones, however what’s common between them is the fact that they all operate as a single unit where info is stored. The biggest advantage of using a RAID is redundancy as the information on all of the drives is identical at all times, so even in the event that some drive fails for some reason, the data will still be present on the other drives. The general performance will also improve since the reading and writing processes will be split between different drives, so a single one will never be overloaded. There are different kinds of RAIDs where the performance and fault tolerance may vary depending on the specific setup - whether information is written on all drives in real time or it's written on one drive and afterwards mirrored on another, the number of drives are used for the RAID, and many others.
RAID in Shared Website Hosting
The drives which we use for storage with our state-of-the-art cloud web hosting platform are not the classic HDDs, but high-speed solid-state drives (SSD). They function in RAID-Z - a special setup created for the ZFS file system which we work with. Any content that you upload to the shared website hosting account will be held on multiple drives and at least one shall be used as a parity disk. This is a specific drive where an additional bit is included to any content copied on it. In case a disk in the RAID fails, it'll be changed without any service disruptions and the info will be recovered on the new drive by recalculating its bits using the data on the parity disk along with that on the remaining disks. This is done so as to guarantee the integrity of the information and together with the real-time checksum verification which the ZFS file system performs on all drives, you won't ever have to concern yourself with losing any data no matter what.