RAID, or Redundant Array of Independent Disks, is a technology of keeping data on a number hard disks which function 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 separate ones using virtualization software. In any case, identical data is stored on all the drives and the key advantage of employing such a setup is that if a drive breaks down, the data will still be available on the other ones. Using a RAID also improves the performance since the input and output operations will be spread among a few drives. There are several types of RAID dependant upon how many hard drives are used, whether writing is done on all drives in real time or just on one, and how the info is synced between the hard drives - whether it is written in blocks on one drive after another or it is mirrored from one on the others. All of these factors imply that the fault tolerance and the performance between the different RAID types can differ.
RAID in Shared Hosting
The hard disks which we use for storage with our revolutionary cloud Internet hosting platform are not the traditional HDDs, but high-speed solid-state drives (SSD). They work in RAID-Z - a special setup intended for the ZFS file system that we use. Any content that you add to your shared hosting account will be kept on multiple hard drives and at least one shall be used as a parity disk. This is a special drive where a further bit is included to any content copied on it. In the event that a disk in the RAID stops functioning, it'll be changed without any service interruptions and the information will be recovered on the new drive by recalculating its bits using the data on the parity disk plus that on the other disks. This is done in order to ensure the integrity of the data and together with the real-time checksum verification which the ZFS file system executes on all drives, you'll never need to worry about the loss of any information no matter what.
RAID in Semi-dedicated Servers
If you host your websites within a semi-dedicated server account from our company, any content which you upload will be kept on SSD drives which work in RAID-Z. With this form of RAID, at least 1 of the hard drives is employed for parity - when data is synced between the disks, an additional bit is added to it on the parity one. The reasoning behind this is to ensure the integrity of the info which is duplicated to a brand new drive in the event that one of the drives in the RAID breaks down since the content being copied on the brand new disk is recalculated from the info on the standard disk drives and on the parity one. An additional advantage of RAID-Z is that even in case a disk drive stops working, the system can easily switch to a different one instantly without service interruptions of any type. RAID-Z adds an additional level of safety for the content you upload on our cloud Internet hosting platform along with the ZFS file system which uses unique checksums as a way to validate the integrity of every single file.
RAID in VPS Servers
The SSD drives that we use on the machines where we set up VPS servers operate in RAID to make sure that any content that you upload will be available and intact at all times. At least 1 drive is used for parity - one bit of data is added to any data copied on it. In the event that a main drive fails, it is replaced and the information that will be copied on it is calculated between the other drives and the parity one. That’s done to make sure that the correct data is copied and that not a single file is corrupted because the new drive will be a part of the RAID afterwards. Also, we use hard disk drives working in RAID on the backup servers, so in the event that you add this upgrade to your VPS package, you will use an even more reliable Internet hosting service since your content will be available on multiple drives irrespective of any type of unexpected hardware failure.