RAID, or Redundant Array of Independent Disks, is a technology for storing data on several hard disks which function together as one logical unit. The drives could be physical or logical i.e. in the aforementioned case one single drive is divided into independent ones through virtualization software. In either case, exactly the same information is kept on all the drives and the key advantage of employing such a setup is that in the event that a drive stops working, the data will remain available on the other ones. Having a RAID also improves the performance as the input and output operations will be spread among a couple of drives. There are several kinds of RAID depending on how many hard disks are used, whether writing is performed on all drives in real time or just on one, and how the data is synced between the drives - whether it's written in blocks on one drive after another or all of it is mirrored from one on the others. These factors show that the fault tolerance and the performance between the different RAID types could differ.
RAID in Shared Hosting
The hard drives that we use for storage with our innovative cloud web hosting platform are not the standard HDDs, but extremely fast solid-state drives (SSD). They function in RAID-Z - a special setup developed for the ZFS file system that we work with. All the content that you upload to your shared hosting account will be stored on multiple hard drives and at least one of them will be used as a parity disk. This is a special drive where an additional bit is included to any content copied on it. In case a disk in the RAID stops functioning, it will be changed without service interruptions and the information will be rebuilt on the new drive by recalculating its bits using the data on the parity disk plus that on the remaining disks. This is done so as to ensure the integrity of the info and along with the real-time checksum verification that the ZFS file system runs on all drives, you won't ever have to worry about losing any info no matter what.
RAID in Semi-dedicated Servers
The RAID type that we employ for the cloud hosting platform where your semi-dedicated server account will be created is called RAID-Z. What is different about it is that at least 1 of the disks is employed as a parity drive. Put simply, whenever any kind of data is duplicated on this specific drive, one more bit is added to it and in case a defective disk is replaced, the data that will be duplicated on it is a mix of the data on the other hard disks in the RAID and that on the parity one. It's done this way to make sure that the data is intact. Throughout this process, your Internet sites will be functioning normally as RAID-Z enables a whole drive to fail without causing any service disturbances and it simply works by using one of the remaining ones as the main production drive. Employing RAID-Z together with the ZFS file system which uses checksums to ensure that no data will get silently corrupted on our servers, you will never need to worry about the integrity of your files.
RAID in VPS Servers
The physical servers where we generate VPS server work with extremely fast SSD drives that will boost the speed of your websites noticeably. The disk drives operate in RAID to ensure that you won't lose any information as a result of a power loss or a hardware breakdown. The production servers work with a variety of drives where the data is saved and one disk is used for parity i.e. one bit is added to all of the info copied on it, that makes it much easier to recover the website content without loss in case a main drive fails. If you use our backup service, the information will be stored on an independent machine which uses standard hard-disk drives and even though there's no parity one in this case, they are also in a RAID to guarantee that we will have a backup copy of your content at all times. With this particular configuration your info will always be safe as it will be available on a lot of disk drives.