RAID, or Redundant Array of Independent Disks, is a technology of keeping data on several hard disks which work together as one single logical unit. The drives can be physical or logical i.e. in the latter case one single drive is divided into independent ones using virtualization software. In any case, identical info is kept on all of the drives and the key benefit of employing this kind of a setup is that in case a drive breaks down, the data shall still be available on the other ones. Using a RAID also boosts the performance as the input and output operations will be spread among a few drives. There are several kinds of RAID based on how many drives are used, whether writing is carried out on all drives in real time or just on one, and how the info is synchronized between the hard drives - whether it is recorded in blocks on one drive after another or all of it is mirrored from one on the others. All of these factors indicate that the error tolerance and the performance between the various RAID types can differ.
RAID in Hosting
The SSD drives that our cutting-edge cloud web hosting platform uses for storage operate in RAID-Z. This type of RAID is designed to work with the ZFS file system that runs on the platform and it works by using the so-called parity disk - a special drive where info located on the other drives is cloned with an extra bit added to it. In the event that one of the disks stops functioning, your sites shall continue working from the other ones and once we replace the faulty one, the info which will be cloned on it will be rebuilt from what is stored on the other drives as well as the information from the parity disk. This is performed so as to be able to recalculate the elements of each file correctly and to verify the integrity of the data cloned on the new drive. This is another level of security for the information which you upload to your hosting account in addition to the ZFS file system which compares a unique digital fingerprint for each and every file on all the disk drives in real time.