RAID, or Redundant Array of Independent Disks, is a technology for keeping data on several hard disks which operate together as a single logical unit. The drives can be physical or logical i.e. in the aforementioned case one single drive is divided into independent ones using virtualization software. In any case, identical information is saved on all of the drives and the key benefit of employing such a setup is that if a drive fails, the data will still be available on the other ones. Using a RAID also enhances the overall performance since the input and output operations will be spread among several drives. There are several kinds of RAID based on how many hard drives are used, whether writing is performed on all of the drives in real time or just on a single one, and how the data is synced between the hard drives - whether it is written in blocks on one drive after another or all of it is mirrored from one on the others. These factors imply that the fault tolerance as well as the performance between the various RAID types could differ.
RAID in Cloud Hosting
The SSD drives which our cutting-edge cloud Internet hosting platform uses for storage work in RAID-Z. This kind of RAID is developed to work with the ZFS file system which runs on the platform and it works by using the so-called parity disk - a special drive where info stored on the other drives is cloned with an extra bit added to it. In case one of the disks fails, your sites will continue working from the other ones and after we replace the problematic one, the information that will be duplicated on it will be rebuilt from what is stored on the remaining drives as well as the info from the parity disk. This is performed in order to be able to recalculate the elements of every single file correctly and to validate the integrity of the info duplicated on the new drive. This is an additional level of security for the info you upload to your cloud hosting account in addition to the ZFS file system which compares a special digital fingerprint for every single file on all the hard drives in real time.