RAID, which stands short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that permits a system to use multiple hard drives as a single logical unit. Simply put, all the drives are used as one and the information on all of them is the same. This type of a setup has 2 major advantages over using just a single drive to keep data - the first is redundancy, so in the event that one drive breaks down, the information will be accessible from the remaining ones, and the second is better performance because the input/output, or reading/writing operations will be spread among multiple drives. There're different RAID types in accordance with what amount of drives are employed, if reading and writing are both executed from all the drives simultaneously, if data is written in blocks on one drive after another or is mirrored between drives in the same time, etc. According to the exact setup, the fault tolerance and the performance could differ.
RAID in Cloud Web Hosting
All content that you upload to your new cloud web hosting account will be saved on quick SSD drives which operate in RAID-Z. This configuration is built to use the ZFS file system which runs on our cloud hosting platform and it adds one more level of security for your site content on top of the real-time checksum authentication which ZFS uses to guarantee the integrity of the data. With RAID-Z, the data is saved on a number of disks and at least one is a parity disk - whenever data is written on it, an additional bit is added, so if any drive stops functioning for whatever reason, the integrity of the info can be verified by recalculating its bits based on what is stored on the production hard drives and on the parity one. With RAID-Z, the operation of our system won't be interrupted and it will continue operating smoothly until the malfunctioning drive is changed and the data is synchronized on it.