RAID, or Redundant Array of Independent Disks, is a technology of storing data on a number hard disk drives which function together as a single logical unit. The drives could be physical or logical i.e. in the second case one drive is divided into separate ones using virtualization software. Either way, exactly the same info is kept on all of the drives and the key benefit of using this type of a setup is that in the event that a drive stops working, the data will remain available on the remaining ones. Having a RAID also enhances the performance since the input and output operations will be spread among several drives. There are several kinds of RAID depending on how many drives are used, whether writing is carried out on all of the drives in real time or just on a single one, and how the information is synced between the drives - whether it's written in blocks on one drive after another or all of it is mirrored from one on the others. These factors suggest that the fault tolerance and the performance between the different RAID types may vary.
RAID in Cloud Hosting
The SSD drives which our cutting-edge cloud Internet hosting platform uses for storage operate in RAID-Z. This sort 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 stored on the other drives is copied with an additional bit added to it. In the event that one of the disks stops working, your websites shall continue working from the other ones and as soon as we replace the malfunctioning one, the information that will be duplicated on it will be rebuilt from what is stored on the other drives together with the information from the parity disk. This is done so as to be able to recalculate the elements of every file correctly and to validate the integrity of the data copied on the new drive. This is one more level of security for the content that you upload to your cloud hosting account together with the ZFS file system that analyzes a special digital fingerprint for every single file on all drives in real time.
RAID in Semi-dedicated Hosting
The data uploaded to any semi-dedicated hosting account is kept on SSD drives which work in RAID-Z. One of the drives in this kind of a setup is used for parity - each time data is cloned on it, an additional bit is added. In case a disk happens to be flawed, it will be removed from the RAID without interrupting the functioning of the sites because the data will load from the remaining drives, and when a brand new drive is included, the info which will be copied on it will be a blend between the info on the parity disk and data kept on the other hard disks in the RAID. This is done in order to ensure that the info that is being cloned is correct, so once the new drive is rebuilt, it could be integrated into the RAID as a production one. This is an extra warranty for the integrity of your info since the ZFS file system that runs on our cloud web hosting platform compares a unique checksum of all the copies of your files on the different drives to be able to avoid any possibility of silent data corruption.