Redundant Array of Independent Disks, or RAID, is a method of keeping content on several hard disks simultaneously. A RAID might be software or hardware based on the HDDs that are used - physical or logical ones, however what’s common between them is that they all perform as just a single unit where information is kept. The top advantage of employing a RAID is redundancy because the information on all drives shall be identical all of the time, so even in case one of the drives fails for whatever reason, the information will still be available on the remaining drives. The overall performance will also improve as the reading and writing processes could be split between multiple drives, so a single one won't be overloaded. There are different types of RAIDs where the effectiveness and fault tolerance could differ depending on the specific setup - whether information is written on all the drives in real time or it is written on one drive and afterwards mirrored on another, what number of drives are used for the RAID, etc.
RAID in Website Hosting
The disk drives which we use for storage with our state-of-the-art cloud Internet hosting platform are not the traditional HDDs, but super fast NVMes. They work in RAID-Z - a special setup created for the ZFS file system that we employ. Any content that you add to the website hosting account will be stored on multiple hard disks and at least one will be employed as a parity disk. This is a specific drive where a further bit is included to any content copied on it. In case a disk in the RAID fails, it'll be replaced without any service interruptions and the info 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 along with the real-time checksum validation which the ZFS file system performs on all drives, you'll never have to worry about losing any data no matter what.
RAID in Semi-dedicated Servers
The RAID type that we use for the cloud hosting platform where your semi-dedicated server account shall be created is called RAID-Z. What's different about it is that at least 1 of the disks is used as a parity drive. Simply put, whenever any kind of data is cloned on this particular hard drive, one more bit is added to it and in case a malfunctioning disk is changed, the data which will be copied on it is a mix of the data on the other hard drives in the RAID and that on the parity one. It's done this way to make sure that your data is intact. During this process, your Internet sites will be up and running normally as RAID-Z makes it possible for a whole drive to fail without service disruptions and it simply uses one of the remaining ones as the main production drive. Using RAID-Z together with the ZFS file system which uses checksums to warrant that no data shall get silently corrupted on our servers, you will not have to worry about the integrity of your files.