RAID, which is short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which permits a system to use a number of hard drives as one single logical unit. Put simply, all of the drives are used as one and the info on all of them is identical. This type of a configuration has two huge advantages over using just a single drive to store data - the first is redundancy, so in case one drive fails, the information will be accessed through the others, and the second is improved performance because the input/output, or reading/writing operations will be distributed among multiple drives. You can find different RAID types depending on the number of drives are used, if reading and writing are both done from all the drives concurrently, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, and so on. Depending on the exact setup, the error tolerance and the performance vary.
RAID in Cloud Hosting
The hard disks which we use for storage with our innovative cloud Internet hosting platform are not the traditional HDDs, but quick solid-state drives (SSD). They operate in RAID-Z - a special setup developed for the ZFS file system which we use. Any content that you upload to your cloud hosting account will be held on multiple hard drives and at least 1 shall be used as a parity disk. This is a special drive where a further 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 data will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk along with that on the other disks. This is done so as to guarantee the integrity of the information and together with the real-time checksum authentication which the ZFS file system runs on all drives, you won't ever need to concern yourself with losing any data no matter what.