RAID, or Redundant Array of Independent Disks, is a technology of keeping data on several hard disk drives that operate together as a single logical unit. The drives could be physical or logical i.e. in the latter case one single drive is split into independent ones via virtualization software. In any case, exactly the same data is saved on all of the drives and the key benefit of employing this kind of a setup is that if a drive fails, the data shall still be available on the other ones. Employing a RAID also improves the overall performance since the input and output operations will be spread among several drives. There are several kinds of RAID depending on how many hard drives are used, whether writing is carried out on all the drives in real time or just on a single one, and how the data is synchronized between the drives - whether it is recorded in blocks on one drive after another or it is mirrored from one on the others. These factors show that the fault tolerance as well as the performance between the different RAID types can vary.
RAID in Cloud Hosting
The hard drives that we employ for storage with our innovative cloud web hosting platform are not the standard HDDs, but quick solid-state drives (SSD). They function in RAID-Z - a special setup intended for the ZFS file system which we work with. All the content that you add to the cloud hosting account will be stored on multiple disk drives and at least 1 shall be used as a parity disk. This is a special drive where an additional bit is included to any content copied on it. In the event that a disk in the RAID stops working, it'll be replaced with no service interruptions and the info will be recovered on the new drive by recalculating its bits using the data on the parity disk plus that on the remaining disks. This is done so as to ensure the integrity of the info and along with the real-time checksum validation which the ZFS file system performs on all drives, you won't ever have to concern yourself with the loss of any information no matter what.