RAID, or Redundant Array of Independent Disks, is a technology for keeping data on multiple hard disks that function together as one single logical unit. The drives could be physical or logical i.e. in the latter case a single drive is divided into individual ones through virtualization software. In any case, the same info is stored on all the drives and the main advantage of using this kind of a setup is that if a drive fails, the data will still be available on the remaining ones. Having a RAID also improves the performance since the input and output operations will be spread among a number of drives. There are several types of RAID depending on how many hard drives are used, whether writing is performed on all the drives in real time or just on one, and how the data is synchronized between the drives - whether it is written in blocks on one drive after another or it is mirrored from one on the others. All these factors indicate that the fault tolerance as well as the performance between the different RAID types could differ.
RAID in Hosting
Our state-of-the-art cloud hosting platform where all hosting accounts are created uses quick SSD drives as opposed to the classic HDDs, and they function in RAID-Z. With this setup, a number of hard disk drives work together and at least one is a dedicated parity disk. Put simply, when data is written on the remaining drives, it is copied on the parity one adding an extra bit. This is performed for redundancy as even if some drive fails or falls out of the RAID for some reason, the info can be rebuilt and verified thanks to the parity disk and the data recorded on the other ones, so not a thing will be lost and there won't be any service disturbances. This is another level of security for your info together with the cutting-edge ZFS file system that uses checksums to make sure that all of the data on our servers is intact and is not silently corrupted.