RAID, which is short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that allows a system to take advantage of a number of hard drives as a single logical unit. Put simply, all the drives are used as one and the information on all of them is the same. Such a setup has two major advantages over using a single drive to store data - the first is redundancy, so if one drive breaks down, the info will be accessible from the others, and the second is better performance as the input/output, or reading/writing operations will be distributed among several drives. There're different RAID types depending on how many drives are employed, whether reading and writing are both performed from all of the drives concurrently, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, etc. Determined by the exact setup, the error tolerance and the performance vary.
RAID in Shared Hosting
The SSD drives that our cutting-edge cloud web hosting platform uses for storage function in RAID-Z. This type of RAID is created to work with the ZFS file system which runs on the platform and it uses the so-called parity disk - a specific drive where data kept on the other drives is copied with an additional bit added to it. In case one of the disks fails, your Internet sites will continue working from the other ones and once we replace the bad one, the info that will be cloned on it will be recovered from what is stored on the rest of the drives as well as the information from the parity disk. This is done in order to be able to recalculate the elements of each file correctly and to confirm the integrity of the information cloned on the new drive. This is an additional level of security for the content which you upload to your shared hosting account together with the ZFS file system which compares a unique digital fingerprint for each file on all drives in real time.