RAID, or Redundant Array of Independent Disks, is a technology for storing data on multiple hard drives which work together as a single logical unit. The drives could be physical or logical i.e. in the aforementioned case a single drive is split into different ones via virtualization software. In any case, identical info is stored on all the drives and the main advantage of employing such a setup is that if a drive fails, the data will still be available on the remaining ones. Employing a RAID also improves the performance since the input and output operations will be spread among a couple of drives. There are several types 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 data is synchronized between the drives - whether it's recorded in blocks on one drive after another or it is mirrored from one on the others. All these factors suggest that the error tolerance as well as the performance between the different RAID types can differ.
RAID in Shared Hosting
The disk drives which we employ for storage with our revolutionary cloud Internet hosting platform are not the standard HDDs, but super fast solid-state drives (SSD). They operate in RAID-Z - a special setup created for the ZFS file system which we employ. All of the content that you add to the shared hosting account will be saved on multiple disk drives and at least one of them shall be used as a parity disk. This is a special drive where an extra bit is included to any content copied on it. If a disk in the RAID stops functioning, it will 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 remaining disks. This is done in order to guarantee the integrity of the data and together with the real-time checksum authentication that the ZFS file system runs on all drives, you will never have to concern yourself with the loss of any data no matter what.
RAID in Semi-dedicated Servers
If you host your Internet sites within a semi-dedicated server account from our firm, any content that you upload will be held on SSD drives which work in RAID-Z. With this kind of RAID, at least 1 of the drives is used for parity - when data is synced between the disks, an extra bit is added to it on the parity one. The reasoning behind this is to guarantee the integrity of the data that is copied to a brand new drive in the event that one of the hard drives in the RAID stops working as the content being copied on the new disk is recalculated from the info on the standard hard drives and on the parity one. Another advantage of RAID-Z is the fact that even in the event that a disk drive stops functioning, the system can easily switch to a different one right away without service interruptions of any sort. RAID-Z adds one more level of security for the content you upload on our cloud web hosting platform together with the ZFS file system which uses unique checksums to authenticate the integrity of every single file.
RAID in VPS Servers
The SSD drives which we use on the physical machines where we create VPS servers function in RAID to ensure that any content which you upload will be available and intact all of the time. At least a single drive is employed for parity - one bit of information is added to any data copied on it. If a main drive fails, it is replaced and the info that will be cloned on it is calculated between the remaining drives and the parity one. This is done to ensure that the needed data is copied and that no file is corrupted since the new drive will be used in the RAID afterwards. In addition, we use hard disks functioning in RAID on the backup servers, so if you add this upgrade to your VPS plan, you'll use an even more reliable hosting service because your content will be available on multiple drives irrespective of any type of unexpected hardware failure.