Redundant Array of Independent Disks, or RAID, is a way of keeping content on a number of hard drives at the same time. A RAID might be software or hardware based on the hard drives that are used - physical or logical ones, yet what is common between them is the fact that they all function as just one single unit where information is saved. The biggest advantage of employing a RAID is redundancy because the data on all drives shall be exactly the same all the time, so even in the event that one of the drives fails for some reason, the information will still be available on the remaining drives. The general performance is also better since the reading and writing processes will be split between multiple drives, so a single one can't be overloaded. There're different kinds of RAIDs where the capabilities and fault tolerance could differ based on the exact setup - whether data is written on all drives in real time or it's written on one drive and then mirrored on another, what number of drives are used for the RAID, and many others.
RAID in Shared Hosting
The disk drives which we use for storage with our outstanding 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 which we employ. All of the content that you upload to the shared hosting
account will be stored on multiple drives and at least 1 will be used as a parity disk. This is a specific drive where a further bit is included to any content copied on it. If a disk in the RAID stops working, it'll be replaced without any service disruptions and the data will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk plus that on the other disks. This is done in order to ensure the integrity of the data and along with the real-time checksum authentication which the ZFS file system runs on all drives, you won't ever need to worry about the loss of any data no matter what.
RAID in Semi-dedicated Hosting
The RAID type which we employ for the cloud Internet hosting platform where your semi-dedicated hosting
account shall be created is named RAID-Z. What is different about it is that at least one of the disks is used as a parity drive. Put simply, whenever any data is copied on this specific disk drive, one more bit is added to it and in case a malfunctioning disk is replaced, the info that will be duplicated on it is a mix of the data on the other disk drives in the RAID and that on the parity one. We do this to ensure that the data is intact. During this process, your sites will be functioning normally because RAID-Z enables an entire drive to fail without service disruptions 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 that uses checksums to guarantee that no data can get silently corrupted on our servers, you won't ever need to worry about the integrity of your files.