RAID, or Redundant Array of Independent Disks, is a technology for keeping data on multiple hard drives which operate together as one single logical unit. The drives can be physical or logical i.e. in the aforementioned case one single drive is divided into separate ones through virtualization software. In any case, the very same info is stored on all of the drives and the key advantage of using such a setup is that if a drive breaks down, the data will remain available on the other ones. Using a RAID also enhances the performance as the input and output operations will be spread among a couple of drives. There are several types of RAID depending on how many hard drives are used, whether writing is performed on all of the drives in real time or just on a single one, and how the information is synced between the hard drives - whether it is written in blocks on one drive after another or all of it is mirrored from one on the others. All of these factors show that the fault tolerance and the performance between the different RAID types may vary.
RAID in Shared Web Hosting
The disk drives that we employ for storage with our state-of-the-art cloud web hosting platform are not the traditional HDDs, but super fast NVMes. They operate in RAID-Z - a special setup designed for the ZFS file system which we employ. All the content that you add to your shared web hosting account will be saved on multiple hard drives and at least 1 shall be used as a parity disk. This is a specific drive where an additional bit is included to any content copied on it. If a disk in the RAID stops working, it'll be replaced without any service disruptions and the data will be rebuilt on the new drive by recalculating its bits using the data on the parity disk along with that on the other disks. This is done so as to ensure the integrity of the information and together with the real-time checksum authentication which the ZFS file system runs on all drives, you will never need to be concerned about the loss of any info no matter what.
RAID in Semi-dedicated Servers
The data uploaded to any semi-dedicated server account is stored on NVMe drives which work in RAID-Z. One of the drives in such a setup is used for parity - every time data is copied on it, an extra bit is added. If a disk happens to be problematic, it will be taken out of the RAID without interrupting the functioning of the Internet sites as the data will load from the other drives, and when a new drive is included, the data that will be cloned on it will be a mix between the data on the parity disk and data saved on the other hard drives in the RAID. That is done so as to guarantee that the data that is being copied is accurate, so as soon as the new drive is rebuilt, it could be integrated into the RAID as a production one. This is an extra guarantee for the integrity of your data as the ZFS file system which runs on our cloud Internet hosting platform analyzes a unique checksum of all copies of the files on the different drives to be able to avoid any probability of silent data corruption.
RAID in VPS Servers
The NVMe drives which we use on the physical machines where we set up VPS servers operate in RAID to ensure that any content that you upload will be available and intact all the time. At least 1 drive is used for parity - one bit of info is added to any data copied on it. In the event that a main drive breaks down, it is changed and the data which will be duplicated on it is calculated between the rest of the drives and the parity one. It's done this way to ensure that the right info is copied and that no file is corrupted as the new drive will be a part of the RAID afterwards. We also use hard drives operating in RAID on the backup servers, so if you add this upgrade to your VPS package, you shall use an even more reliable hosting service since your content will be available on multiple drives regardless of any unexpected hardware failure.