RAID, or Redundant Array of Independent Disks, is a technology of keeping data on a number hard drives which operate together as a single logical unit. The drives can be physical or logical i.e. in the second case one single drive is split into individual ones using virtualization software. In any case, exactly the same information is kept on all the drives and the main benefit of using this kind of a setup is that in the event that a drive stops working, the data will still be available on the remaining ones. Employing a RAID also improves the overall performance since the input and output operations will be spread among a couple of drives. There are several kinds of RAID based on how many hard drives are used, whether writing is carried out on all drives in real time or just on a single one, and how the information is synchronized between the drives - whether it is written in blocks on one drive after another or all of it is mirrored from one on the others. All these factors suggest that the error tolerance and the performance between the various RAID types may vary.
RAID in Cloud Hosting
The hard disks which we employ for storage with our outstanding cloud Internet hosting platform are not the classic HDDs, but fast solid-state drives (SSD). They operate in RAID-Z - a special setup designed for the ZFS file system which we use. Any content that you add to your cloud hosting account will be held on multiple disk drives and at least one of them shall be used as a parity disk. This is a specific drive where an extra bit is added to any content copied on it. If a disk in the RAID stops working, it will be changed without service interruptions and the data will be rebuilt 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 in order to ensure the integrity of the data and along with the real-time checksum authentication which the ZFS file system performs on all drives, you won't ever have to worry about losing any info no matter what.