RAID, or Redundant Array of Independent Disks, is a technology for storing data on a number hard disks that operate together as one logical unit. The drives can be physical or logical i.e. in the second case a single drive is divided into different ones via virtualization software. In either case, the same info is saved on all of the drives and the main benefit of using such a setup is that in the event that a drive breaks down, the data shall still be available on the remaining ones. Employing a RAID also enhances the 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 carried out on all of the drives in real time or just on one, and how the information is synchronized 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 suggest that the error tolerance and the performance between the various RAID types may vary.
RAID in Shared Hosting
The revolutionary cloud hosting platform where all shared hosting accounts are generated employs super fast SSD drives as an alternative to the classic HDDs, and they operate in RAID-Z. With this setup, a number of hard drives operate together and at least one is a dedicated parity disk. Basically, when data is written on the rest of the drives, it's copied on the parity one adding an extra bit. This is done for redundancy as even in case some drive fails or falls out of the RAID for whatever reason, the data can be rebuilt and verified using the parity disk and the data stored on the other ones, so nothing will be lost and there won't be any service disturbances. This is another level of security for your info together with the revolutionary ZFS file system that uses checksums to guarantee that all data on our servers is undamaged and is not silently corrupted.