Redundant Array of Independent Disks, or RAID, is a way of storing content on several hard drives at the same time. A RAID can be software or hardware depending on the HDDs which are used - physical or logical ones, but what is common between them is that they all perform as a single unit where info is kept. The biggest advantage of employing a RAID is redundancy as the info on all of the drives is identical at all times, so even in the event that one of the drives fails for some reason, the info will still be available on the other drives. The general performance is also better since the reading and writing processes can be split between different drives, so a single one can't be overloaded. There're different sorts of RAIDs where the functionality and fault tolerance may vary according to the exact setup - whether info is written on all drives in real time or it is written on a single drive and then mirrored on another, what amount of drives are used for the RAID, etcetera.
RAID in Cloud Hosting
The advanced cloud web hosting platform where all cloud hosting accounts are generated uses fast SSD drives rather than the traditional HDDs, and they function in RAID-Z. With this configuration, multiple hard drives function together and at least one of them is a dedicated parity disk. Simply put, when data is written on the rest of the drives, it's cloned on the parity one adding an extra bit. This is performed for redundancy as even in case a drive fails or falls out of the RAID for whatever reason, the information can be rebuilt and verified thanks to the parity disk and the data saved on the other ones, thus absolutely nothing will be lost and there will be no service interruptions. This is one more level of security for your data along with the advanced ZFS file system that uses checksums to guarantee that all of the data on our servers is intact and is not silently corrupted.
RAID in Semi-dedicated Hosting
The RAID type that we employ for the cloud hosting platform where your semi-dedicated hosting account will be created is called RAID-Z. What's different about it is that at least one of the disks is used as a parity drive. Put simply, whenever any kind of data is duplicated on this special disk drive, one more bit is included to it and in case a defective disk is replaced, the data that will be duplicated on it is a combination of the data on the other hard drives in the RAID and that on the parity one. We do this to guarantee that the info is intact. During this process, your sites will be functioning normally as RAID-Z enables an entire drive to fail without any service interruptions 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 guarantee 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 Hosting
The SSD drives which we use on the physical machines where we generate virtual private servers operate in RAID to ensure that any content you upload will be available and intact at all times. At least 1 drive is employed for parity - one bit of info is added to any data copied on it. In case a main drive stops working, it is replaced and the data that will be duplicated on it is calculated between the remaining drives and the parity one. This is done to ensure that the correct information is copied and that no file is corrupted since the new drive will be used in the RAID afterwards. Also, we use hard disk drives operating 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 Internet hosting service since your content will be available on multiple drives regardless of any sort of unforeseen hardware failure.