RAID, or Redundant Array of Independent Disks, is a technology of storing data on multiple hard drives which operate together as one logical unit. The drives could be physical or logical i.e. in the latter case one single drive is divided into independent ones via virtualization software. Either way, identical data is stored on all the drives and the main advantage of using this kind of a setup is that if a drive breaks down, the data will remain available on the other ones. Having a RAID also boosts the performance because the input and output operations will be spread among a few drives. There are several types of RAID dependant upon how many hard drives are used, whether writing is carried out on all the drives in real time or just on one, and how the data is synced between the hard drives - whether it is written in blocks on one drive after another or it is mirrored from one on the others. All of these factors mean that the error tolerance as well as the performance between the various RAID types could differ.
RAID in Shared Website Hosting
The disk drives that we employ for storage with our state-of-the-art cloud web hosting platform are not the classic HDDs, but fast solid-state drives (SSD). They operate in RAID-Z - a special setup intended for the ZFS file system that we work with. Any content that you add to the shared website hosting account will be held on multiple disk drives and at least one shall 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 fails, it'll be replaced without service interruptions and the info will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk plus that on the remaining disks. This is done in order to guarantee the integrity of the info and along with the real-time checksum validation which the ZFS file system executes on all drives, you won't ever have to be concerned about the loss of any info no matter what.