RAID, or Redundant Array of Independent Disks, is a technology of storing data on multiple hard disk drives that function together as a single logical unit. The drives can be physical or logical i.e. in the aforementioned case one single drive is divided into different ones through virtualization software. Either way, exactly the same data is kept on all drives and the key advantage of employing this type of a setup is that in case a drive fails, the data shall still be available on the remaining ones. Having a RAID also improves the overall performance because the input and output operations will be spread among a number of drives. There are several kinds of RAID depending on how many hard disks are used, whether writing is carried out on all of the drives in real time or just on one, and how the information 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 mean that the fault tolerance as well as the performance between the different RAID types can differ.
RAID in Cloud Hosting
The hard disks that we use for storage with our innovative cloud Internet hosting platform are not the traditional HDDs, but high-speed solid-state drives (SSD). They work in RAID-Z - a special setup created for the ZFS file system which we use. All the content that you upload to the cloud hosting
account will be saved on multiple drives and at least one will be employed as a parity disk. This is a special drive where an extra bit is included to any content copied on it. In the event that a disk in the RAID fails, it will be changed with no 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 to ensure the integrity of the information and together with the real-time checksum validation that the ZFS file system performs on all drives, you won't ever have to concern yourself with losing any information no matter what.
RAID in Semi-dedicated Servers
The RAID type that we employ for the cloud Internet hosting platform where your semi-dedicated server
account will be created is known as RAID-Z. What is different about it is that at least 1 of the disks is used as a parity drive. Simply put, whenever any data is cloned on this special drive, one more bit is included to it and in case a problematic disk is changed, the data which will be copied on it is a mix of the data on the remaining hard disks in the RAID and that on the parity one. We do this to make sure that the data is intact. Throughout this process, your websites will be working normally as RAID-Z allows for a whole drive to fail without causing any service disruptions and it simply uses one of the remaining ones as the main production drive. Employing RAID-Z together with the ZFS file system that uses checksums to ensure that no data shall get silently corrupted on our servers, you will not have to worry about the integrity of your files.
RAID in VPS Servers
The SSD drives that we use on the physical machines where we generate VPS servers
work in RAID to ensure that any content you upload will be available and intact at all times. At least one drive is used for parity - one bit of data is added to any data cloned on it. In case a main drive stops working, it is changed and the data that will be duplicated on it is calculated between the remaining drives and the parity one. It's done this way to ensure that the required info is copied and that not a single file is corrupted because the new drive will be a part of the RAID afterwards. In addition, we use hard drives working in RAID on the backup servers, so in the event that you add this upgrade to your VPS package, you'll use an even more reliable hosting service as your content will be available on multiple drives irrespective of any sort of unforeseen hardware malfunction.