RAID, which is short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which enables a system to use many hard drives as a single logical unit. Simply put, all drives are used as one and the info on all of them is identical. Such a configuration has two key advantages over using a single drive to store data - the first is redundancy, so in the event that one drive breaks down, the information will be accessed through the others, and the second is improved performance since the input/output, or reading/writing operations will be distributed among several drives. There are different RAID types depending on what number of drives are used, if reading and writing are both performed from all the drives at the same time, 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 particular setup, the error tolerance and the performance may vary.
RAID in Cloud Hosting
The drives which we use for storage with our state-of-the-art cloud web hosting platform are not the traditional HDDs, but extremely fast solid-state drives (SSD). They operate in RAID-Z - a special setup designed for the ZFS file system which we work with. Any content that you add to your cloud hosting account will be saved on multiple disk drives and at least 1 shall be used as a parity disk. This is a special drive where an extra bit is included to any content copied on it. In the event that a disk in the RAID fails, it will be changed with no service disturbances and the info will be recovered on the new drive by recalculating its bits using the data on the parity disk along with that on the remaining disks. This is done to ensure the integrity of the info and together with the real-time checksum authentication that the ZFS file system runs on all drives, you won't ever have to worry about the loss of any data no matter what.