RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that makes it possible for a system to use several hard drives as a single logical unit. In other words, all the drives are used as one and the data on all of them is the same. Such a configuration has two huge advantages over using a single drive to save data - the first is redundancy, so if one drive doesn't work, the info will be accessed from the remaining ones, and the second one is better performance since the input/output, or reading/writing operations will be distributed among a number of drives. There're different RAID types depending on what number of drives are used, whether reading and writing are both done from all drives simultaneously, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, and so on. Determined by the exact setup, the fault tolerance and the performance may differ.
RAID in Shared Web Hosting
The hard disks which we use for storage with our outstanding cloud Internet hosting platform are not the classic HDDs, but extremely fast solid-state drives (SSD). They function in RAID-Z - a special setup developed for the ZFS file system which we work with. All of the content that you upload to your shared web hosting account will be saved on multiple hard drives and at least one will be used as a parity disk. This is a special drive where an additional bit is included to any content copied on it. In the event that a disk in the RAID stops working, it will be replaced without any service interruptions and the data will be rebuilt on the new drive by recalculating its bits using the data on the parity disk plus that on the other disks. This is done so as to ensure the integrity of the data and along with the real-time checksum verification which the ZFS file system performs on all drives, you'll never need to worry about losing any info no matter what.
RAID in Semi-dedicated Servers
The RAID type that we use for the cloud Internet hosting platform where your semi-dedicated server account shall be created is called RAID-Z. What's different about it is that at least 1 of the disks is used as a parity drive. Put simply, whenever any kind of data is cloned on this specific drive, one more bit is included to it and in the event that a faulty disk is changed, the data that will be cloned on it is a mix of the data on the remaining disk drives in the RAID and that on the parity one. We do this to guarantee that the info is intact. During this process, your sites will be working normally because RAID-Z makes it possible for an entire drive to fail without causing any service disturbances and it simply uses one of the other ones as the main production drive. Using RAID-Z together with the ZFS file system which uses checksums to ensure that no data shall get silently corrupted on our servers, you'll never need to worry about the integrity of your files.