RAID, or Redundant Array of Independent Disks, is a technology of storing data on a number hard disks which operate together as a single logical unit. The drives can be physical or logical i.e. in the second case one single drive is split into different ones using virtualization software. Either way, exactly the same information is saved on all the drives and the main benefit of using this kind of a setup is that if a drive fails, the data shall still be available on the remaining ones. Having a RAID also improves the overall performance since the input and output operations will be spread among several drives. There are several types of RAID dependant upon how many hard drives are used, whether writing is carried out on all drives in real time or just on one, and how the information is synced between the drives - whether it's recorded in blocks on one drive after another or it is mirrored from one on the others. All of these factors mean that the fault tolerance and the performance between the different RAID types may differ.
RAID in Cloud Hosting
The SSD drives which our cutting-edge cloud Internet hosting platform employs for storage function in RAID-Z. This sort 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 stored on the other drives is cloned with an extra bit added to it. In case one of the disks stops functioning, your websites shall continue working from the other ones and after we replace the bad 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 information from the parity disk. This is done so as to be able to recalculate the elements of each and every file properly and to verify the integrity of the info cloned on the new drive. This is another level of security for the information that you upload to your cloud hosting account together with the ZFS file system that compares a unique digital fingerprint for each and every file on all hard drives in real time.