Redundant Array of Independent Disks, or RAID, is a method of keeping content on multiple hard disk drives concurrently. A RAID can be software or hardware based on the hard drives which are used - physical or logical ones, but what’s common between them is that they all operate as just a single unit where information is kept. The biggest advantage of employing a RAID is redundancy because the information on all of the drives will be the same at all times, so even in the event that one of the drives fails for whatever reason, the info will still be present on the rest of the drives. The overall performance is also better because the reading and writing processes can be split between multiple drives, so a single one won't be overloaded. There're different types of RAIDs where the performance and fault tolerance can vary depending on the particular setup - whether info is written on all the drives in real time or it's written on a single drive and then mirrored on another, the number of drives are used for the RAID, etcetera.
RAID in Hosting
The SSD drives that our cutting-edge cloud web hosting platform employs for storage work in RAID-Z. This sort of RAID is created to work with the ZFS file system that runs on the platform and it uses the so-called parity disk - a specific drive where data saved on the other drives is cloned with an additional bit added to it. In case one of the disks stops working, your sites will continue working from the other ones and as soon as we replace the faulty one, the data that will be copied on it will be rebuilt from what is stored on the remaining drives together with the information from the parity disk. This is performed so as to be able to recalculate the elements of each file correctly and to validate the integrity of the data copied on the new drive. This is an additional level of security for the content you upload to your hosting account along with the ZFS file system which compares a unique digital fingerprint for every single file on all disk drives in real time.