RAID, or Redundant Array of Independent Disks, is a technology of keeping data on several hard drives which operate together as one single logical unit. The drives could be physical or logical i.e. in the second case a single drive is divided into individual ones via virtualization software. Either way, the same information is stored on all drives and the basic advantage of using this kind of a setup is that if a drive breaks down, the data shall still be available on the other ones. Employing a RAID also boosts the overall performance as the input and output operations will be spread among several drives. There are several kinds of RAID based on how many hard disks are used, whether writing is carried out on all drives in real time or just on one, and how the data 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 mean that the error tolerance and the performance between the various RAID types could differ.

RAID in Semi-dedicated Servers

The data uploaded to any semi-dedicated server account is stored on SSD drives which function in RAID-Z. One of the drives in this kind of a configuration is used for parity - each time data is cloned on it, an extra bit is added. In case a disk turns out to be defective, it will be taken out of the RAID without disturbing the operation of the sites because the data will load from the other drives, and when a brand new drive is added, the data that will be cloned on it will be a combination between the data on the parity disk and data stored on the other hard drives in the RAID. That is done in order to guarantee that the information that is being cloned is correct, so as soon as the new drive is rebuilt, it can be incorporated into the RAID as a production one. This is an extra guarantee for the integrity of your info since the ZFS file system which runs on our cloud Internet hosting platform compares a unique checksum of all of the copies of your files on the different drives so as to avoid any chance of silent data corruption.