Redundant Array of Independent Disks, or RAID, is a method of saving content on a number of hard disk drives simultaneously. A RAID might be software or hardware depending on the drives that are used - physical or logical ones, still what is common between them is that they all perform as just one single unit where info is kept. The biggest advantage of using a RAID is redundancy because the data on all of the drives will be the same at all times, so even if some drive fails for whatever reason, the data will still be present on the rest of the drives. The general performance is also better as the reading and writing processes can be split between a number of drives, so a single one will never be overloaded. There are different types of RAIDs where the effectiveness and fault tolerance could differ according to the exact setup - whether information is written on all of the drives in real time or it's written on one drive and afterwards mirrored on another, what amount of drives are used for the RAID, and many others.
RAID in Shared Hosting
The advanced cloud Internet hosting platform where all shared hosting accounts are generated uses fast SSD drives as an alternative to the classic HDDs, and they work in RAID-Z. With this setup, several hard drives operate together and at least one is a dedicated parity disk. In simple terms, when data is written on the other drives, it is copied on the parity one adding an extra bit. This is performed for redundancy as even if some drive fails or falls out of the RAID for whatever reason, the data can be rebuilt and verified thanks to the parity disk and the data recorded on the other ones, so not a thing will be lost and there will be no service interruptions. This is one more level of security for your info along with the advanced ZFS file system that uses checksums to ensure that all the data on our servers is undamaged and is not silently corrupted.
RAID in VPS Servers
The physical servers where we generate VPS server work with quick SSD drives that will boost the speed of your websites significantly. The drives operate in RAID to ensure that you won't lose any info because of a power loss or a hardware failure. The production servers take advantage of multiple drives where the information is saved and one disk is used for parity i.e. one bit is added to all the data copied on it, which makes it much easier to restore the site content without loss in case a main drive fails. In case you pick our backup service, the info will be kept on an independent machine that uses standard hard-disk drives and although there's no parity one in this case, they are also in a RAID to ensure that we will have a backup of your site content all the time. With this particular configuration your information will always be safe because it will be available on a lot of disk drives.