RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which permits a system to use multiple hard drives as one single logical unit. To put it differently, all of the drives are used as one and the info on all of them is the same. This kind of a configuration has 2 major advantages over using just a single drive to store data - the first is redundancy, so in the event that one drive breaks down, the information will be accessed from the others, and the second one is improved performance as the input/output, or reading/writing operations will be spread among a number of drives. You can find different RAID types based on what amount of drives are employed, if reading and writing are both done from all the drives simultaneously, if data is written in blocks on one drive after another or is mirrored between drives in the same time, and so on. Determined by the exact setup, the error tolerance and the performance vary.
RAID in Cloud Web Hosting
The hard drives that we employ for storage with our state-of-the-art cloud Internet hosting platform are not the classic HDDs, but high-speed solid-state drives (SSD). They operate in RAID-Z - a special setup created for the ZFS file system which we use. Any content that you add to the cloud web hosting account will be held on multiple disk drives and at least one shall be used as a parity disk. This is a special drive where an additional bit is included to any content copied on it. If a disk in the RAID fails, it'll be changed without service interruptions and the information will be recovered on the new drive by recalculating its bits using the data on the parity disk plus that on the other disks. This is done in order to guarantee the integrity of the information and together with the real-time checksum validation that the ZFS file system runs on all drives, you will never have to concern yourself with losing any information no matter what.