RAID, or Redundant Array of Independent Disks, is a technology for keeping data on a number hard drives which work together as a single logical unit. The drives could be physical or logical i.e. in the second case a single drive is split into separate ones through virtualization software. In either case, identical information is saved on all drives and the key advantage of employing such a setup is that in case a drive stops working, the data will still be available on the other ones. Having a RAID also improves the overall performance because the input and output operations will be spread among a few drives. There are several types of RAID based on how many drives are used, whether writing is done on all of the drives in real time or just on one, and how the info is synchronized between the drives - whether it's written in blocks on one drive after another or all of it is mirrored from one on the others. All of these factors suggest that the error tolerance and the performance between the different RAID types could differ.
RAID in Shared Web Hosting
The SSD drives that our cutting-edge cloud hosting platform employs for storage operate in RAID-Z. This kind of RAID is intended to work with the ZFS file system that runs on the platform and it takes advantage of the so-called parity disk - a special drive where data located on the other drives is cloned with an additional bit added to it. In case one of the disks stops functioning, your Internet sites shall continue working from the other ones and once we replace the problematic one, the info which will be cloned on it will be recovered from what is stored on the rest of the drives as well as the data from the parity disk. This is performed so as to be able to recalculate the bits of every file adequately and to confirm the integrity of the info cloned on the new drive. This is one more level of security for the content you upload to your shared web hosting account together with the ZFS file system which compares a special digital fingerprint for each and every file on all drives in real time.