RAID, or Redundant Array of Independent Disks, is a technology for keeping data on multiple hard drives which function together as one logical unit. The drives can be physical or logical i.e. in the latter case one single drive is divided into separate ones using virtualization software. In either case, identical info is stored on all the drives and the basic benefit of employing such a setup is that in the event that a drive fails, the data will still be available on the other ones. Using a RAID also improves the overall performance as the input and output operations will be spread among a number of drives. There are several types of RAID depending on how many hard drives are used, whether writing is performed on all the drives in real time or just on a single one, and how the data is synced between the hard drives - whether it is recorded in blocks on one drive after another or it is mirrored from one on the others. These factors imply that the error tolerance and the performance between the different RAID types can vary.
RAID in Shared Web Hosting
The SSD drives which our cutting-edge cloud Internet hosting platform uses for storage operate in RAID-Z. This sort of RAID is intended to work with the ZFS file system which runs on the platform and it employs the so-called parity disk - a special drive where information stored on the other drives is copied with an extra bit added to it. In case one of the disks fails, your websites shall continue working from the other ones and after we replace the faulty one, the data which will be copied on it will be recovered from what is stored on the remaining drives along with the information from the parity disk. This is performed in order to be able to recalculate the elements of each file properly and to verify the integrity of the information cloned on the new drive. This is an additional level of security for the content you upload to your shared web hosting account along with the ZFS file system which compares a special digital fingerprint for each file on all disk drives in real time.
RAID in Semi-dedicated Servers
If you host your sites in a semi-dedicated server account from our company, all of the content which you upload will be held on SSD drives which operate in RAID-Z. With this form of RAID, at least 1 of the hard disks is used for parity - when data is synced between the drives, an additional bit is added to it on the parity one. The purpose behind this is to guarantee the integrity of the info which is duplicated to a brand new drive in case one of the drives in the RAID stops working because the site content being copied on the new disk is recalculated from the data on the standard disk drives and on the parity one. An additional advantage of RAID-Z is the fact that even in case a drive stops working, the system can switch to a different one quickly without service disturbances of any kind. RAID-Z adds an additional level of protection for the content you upload on our cloud Internet hosting platform together with the ZFS file system that uses unique checksums in order to validate the integrity of every single file.
RAID in VPS Servers
The SSD drives that we use on the physical machines where we create VPS servers operate in RAID to make sure that any content which you upload will be available and intact all the time. At least a single drive is employed for parity - one bit of info is added to any data cloned on it. In case a main drive breaks down, it is changed and the info which will be copied on it is calculated between the other drives and the parity one. This is done to ensure that the correct data is copied and that no file is corrupted because the new drive will be incorporated into the RAID afterwards. We also use hard disks functioning in RAID on the backup servers, so in case you add this upgrade to your VPS package, you will use an even more reliable hosting service as your content will be available on multiple drives irrespective of any kind of sudden hardware malfunction.