RAID, or Redundant Array of Independent Disks, is a technology for keeping data on a number hard disk drives that operate together as a single logical unit. The drives could be physical or logical i.e. in the second case a single drive is split into separate ones using virtualization software. In any case, identical info is saved on all of the drives and the main advantage of using this type of a setup is that if a drive stops working, the data will remain available on the other ones. Employing a RAID also boosts the overall performance as the input and output operations will be spread among a couple of drives. There are several kinds of RAID based on how many hard disks are used, whether writing is performed on all of the drives in real time or just on one, and how the information 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. All these factors suggest that the error tolerance and the performance between the various RAID types can vary.
RAID in Web Hosting
The hard disks that we employ for storage with our innovative cloud web hosting platform are not the traditional HDDs, but quick solid-state drives (SSD). They work in RAID-Z - a special setup created for the ZFS file system which we use. Any content that you upload to the web hosting account will be held on multiple disk drives and at least 1 shall be used as a parity disk. This is a special drive where a further bit is added to any content copied on it. In case a disk in the RAID stops functioning, it'll be changed without service disturbances and the data will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk along with that on the remaining disks. This is done to ensure the integrity of the information and together with the real-time checksum validation that the ZFS file system executes on all drives, you'll never need to be concerned about the loss of any data no matter what.
RAID in Semi-dedicated Servers
The info uploaded to any semi-dedicated server account is saved on SSD drives which work in RAID-Z. One of the drives in type of a setup is used for parity - every time data is copied on it, an additional bit is added. In case a disk happens to be faulty, it will be taken out of the RAID without interrupting the operation of the websites since the data will load from the rest of the drives, and when a brand new drive is added, the data that will be copied on it will be a blend between the data on the parity disk and data kept on the other drives in the RAID. That is done to ensure that the data that is being cloned is correct, so as soon as the new drive is rebuilt, it can be included in the RAID as a production one. This is an additional guarantee for the integrity of your data as the ZFS file system that runs on our cloud web hosting platform analyzes a special checksum of all the copies of your files on the various drives to be able to avoid any chance of silent data corruption.
RAID in VPS Servers
The SSD drives which we use on the machines where we generate VPS servers work in RAID to make sure that any content you upload will be available and intact at all times. At least 1 drive is employed for parity - one bit of information is added to any data cloned on it. In case a main drive breaks down, it is changed and the info which will be cloned on it is calculated between the rest of the drives and the parity one. That’s done to ensure that the required info is copied and that not a single file is corrupted because the new drive will be used in the RAID afterwards. Also, we use hard disks functioning in RAID on the backup servers, so in case you add this upgrade to your VPS plan, you shall use an even more reliable hosting service because your content will be available on multiple drives irrespective of any sort of sudden hardware failure.