RAID, which is an acronym of Redundant Array of Independent Disks, is a software or hardware storage virtualization technology that permits a system to use a number of hard drives as one single logical unit. Simply put, all the drives are used as one and the information on all of them is the same. Such a configuration has 2 huge advantages over using a single drive to store data - the first is redundancy, so in the event that one drive breaks down, the information will be accessible through the remaining ones, and the second is improved performance because the input/output, or reading/writing operations will be spread among several drives. There're different RAID types depending on the number of drives are employed, if reading and writing are both done from all of the drives simultaneously, whether data is written in blocks on one drive after another or is mirrored between drives in the same time, etcetera. Depending on the particular setup, the fault tolerance and the performance may differ.
RAID in Hosting
The NVMe drives that our cutting-edge cloud Internet hosting platform uses for storage function in RAID-Z. This kind of RAID is designed to work with the ZFS file system that runs on the platform and it works by using the so-called parity disk - a special drive where information saved on the other drives is duplicated with an additional bit added to it. If one of the disks stops working, your websites will continue working from the other ones and once we replace the problematic one, the info which will be copied on it will be recovered from what is stored on the remaining drives as well as the data from the parity disk. This is done in order to be able to recalculate the bits of each file correctly and to validate the integrity of the information duplicated on the new drive. This is another level of security for the info you upload to your hosting account together with the ZFS file system that compares a special digital fingerprint for every single file on all disk drives in real time.
RAID in Semi-dedicated Hosting
The data uploaded to any semi-dedicated hosting account is stored on NVMe drives which operate in RAID-Z. One of the drives in this kind of a configuration is used for parity - every time data is cloned on it, an extra bit is added. In case a disk turns out to be problematic, it will be removed from the RAID without disturbing the functioning of the Internet sites because the data will load from the other drives, and when a brand new drive is added, the info that will be duplicated on it will be a blend between the information on the parity disk and data saved on the other hard disks in the RAID. This is done to ensure that the info that is being duplicated is accurate, so once the new drive is rebuilt, it could be included in the RAID as a production one. This is an extra guarantee for the integrity of your info since the ZFS file system that runs on our cloud Internet hosting platform analyzes a special checksum of all the copies of the files on the different drives to be able to avoid any probability of silent data corruption.