RAID, or Redundant Array of Independent Disks, is a technology of saving data on several hard drives which function together as a single logical unit. The drives can be physical or logical i.e. in the second case one single drive is split into different ones using virtualization software. Either way, the same data is stored on all drives and the basic advantage of employing this kind of a setup is that if a drive fails, the data shall still be available on the other ones. Having a RAID also boosts the performance since the input and output operations will be spread among a few drives. There are several types of RAID depending on how many hard drives are used, whether writing is done 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 imply that the error tolerance and the performance between the various RAID types could differ.
RAID in Web Hosting
All of the content which you upload to your new web hosting
account will be held on fast SSD drives which operate in RAID-Z. This setup is built to work with the ZFS file system which runs on our cloud web hosting platform and it adds one more level of protection for your site content on top of the real-time checksum authentication that ZFS uses to ensure the integrity of the data. With RAID-Z, the information is stored on several disks and at least one is a parity disk - whenever information is written on it, an extra bit is added, so in the event that any drive fails for some reason, the stability of the data can be verified by recalculating its bits based on what is kept on the production hard drives and on the parity one. With RAID-Z, the functioning of our system will never be interrupted and it will continue functioning flawlessly until the faulty drive is changed and the data is synced on it.
RAID in Semi-dedicated Servers
The RAID type which we use for the cloud web hosting platform where your semi-dedicated server
account shall be created is known as RAID-Z. What is different about it is that at least one of the disks is employed as a parity drive. In simple terms, whenever any kind of data is cloned on this specific disk drive, one more bit is included to it and in the event that a malfunctioning disk is replaced, the information that will be cloned on it is a mix of the data on the other hard drives in the RAID and that on the parity one. We do this to guarantee that the information is intact. Throughout this process, your sites will be functioning normally because RAID-Z allows for a whole drive to fail without causing any service disturbances and it simply works by using one of the remaining ones as the main production drive. Using RAID-Z together with the ZFS file system which uses checksums to warrant that no data will get silently corrupted on our servers, you will never need to worry about the integrity of your files.