RAID, or Redundant Array of Independent Disks, is a technology of saving data on several hard disk drives that work together as one logical unit. The drives can be physical or logical i.e. in the aforementioned case one single drive is divided into different ones using virtualization software. Either way, the very same data is saved on all drives and the main advantage of using this kind of a setup is that if a drive breaks down, the data will still be available on the other ones. Having a RAID also boosts the performance as the input and output operations will be spread among a number of drives. There are several kinds of RAID depending on how many hard disks are used, whether writing is performed on all drives in real time or just on one, and how the information is synchronized between the hard drives - whether it's written in blocks on one drive after another or it is mirrored from one on the others. All of these factors imply that the error tolerance and the performance between the different RAID types could differ.
RAID in Shared Website Hosting
The SSD drives which our cutting-edge cloud Internet hosting platform uses for storage function in RAID-Z. This type 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 info saved on the other drives is duplicated with an extra bit added to it. If one of the disks stops functioning, your sites shall continue working from the other ones and once we replace the bad one, the information that will be cloned on it will be rebuilt from what is stored on the remaining drives as well as the information from the parity disk. This is done in order to be able to recalculate the bits of every file adequately and to authenticate the integrity of the information duplicated on the new drive. This is one more level of security for the content you upload to your shared website hosting account together with the ZFS file system that compares a special digital fingerprint for every single file on all the hard drives in real time.
RAID in Semi-dedicated Hosting
The data uploaded to any semi-dedicated hosting account is stored on SSD drives that function in RAID-Z. One of the drives in such a configuration is used for parity - each time data is copied on it, an additional bit is added. In case a disk happens to be defective, it will be removed from the RAID without disturbing the functioning of the websites because the data will load from the other drives, and when a brand new drive is included, the info that will be duplicated on it will be a combination between the info on the parity disk and data stored on the other drives in the RAID. That is done in order to guarantee that the information that is being cloned is correct, so the moment the new drive is rebuilt, it could be integrated into the RAID as a production one. This is one more guarantee for the integrity of your data because the ZFS file system that runs on our cloud web hosting platform analyzes a special checksum of all copies of the files on the separate drives to avoid any chance of silent data corruption.