RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that permits a system to use many hard drives as one single logical unit. To put it differently, all the drives are used as one and the info on all of them is the same. This type of a configuration has two key advantages over using a single drive to keep data - the first one is redundancy, so in case one drive breaks down, the data will be accessible from the remaining ones, and the second one is improved performance because the input/output, or reading/writing operations will be spread among several drives. There are different RAID types based on what amount of drives are employed, whether reading and writing are both handled from all of the drives concurrently, if data is written in blocks on one drive after another or is mirrored between drives in the same time, and many others. Depending on the particular setup, the fault tolerance and the performance vary.
RAID in Cloud Hosting
The hard disks that we employ for storage with our top-notch cloud Internet hosting platform are not the classic HDDs, but fast solid-state drives (SSD). They function in RAID-Z - a special setup intended for the ZFS file system which we employ. Any content that you upload to your cloud hosting account will be kept on multiple drives and at least one of them will be employed as a parity disk. This is a special drive where an extra bit is included to any content copied on it. In case a disk in the RAID stops working, it will be replaced without service disruptions and the data will be rebuilt 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 data and together with the real-time checksum validation which the ZFS file system executes on all drives, you will never need to worry about the loss of any data no matter what.