RAID, or Redundant Array of Independent Disks, is a technology of saving data on a number hard drives that function together as a single logical unit. The drives could be physical or logical i.e. in the second case one drive is divided into individual ones through virtualization software. Either way, identical information is kept on all drives and the main advantage of using such a setup is that in case a drive breaks down, the data will still be available on the remaining ones. Employing a RAID also boosts the overall performance because the input and output operations will be spread among a number of drives. There are several types of RAID depending on how many hard disks are used, whether writing is performed on all drives in real time or just on one, and how the data is synchronized between the hard drives - whether it's written in blocks on one drive after another or it is mirrored from one on the others. All these factors indicate that the error tolerance as well as the performance between the different RAID types can differ.
RAID in Shared Hosting
The SSD drives that our cutting-edge cloud web hosting platform employs for storage work in RAID-Z. This kind of RAID is created 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 kept on the other drives is copied with an additional bit added to it. In case one of the disks stops working, your websites shall continue working from the other ones and as soon as we replace the bad one, the information which will be duplicated 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 single file adequately and to validate the integrity of the information duplicated on the new drive. This is one more level of security for the information which you upload to your shared hosting account along with the ZFS file system which compares a special digital fingerprint for each and every file on all the hard drives in real time.