Redundant Array of Independent Disks, or RAID, is a way of keeping content on a number of hard disks simultaneously. A RAID could be software or hardware depending on the HDDs which are used - physical or logical ones, however what is common between them is that they all perform as just one single unit where your information is stored. The top advantage of employing a RAID is redundancy as the data on all drives shall be the same at all times, so even if a drive fails for whatever reason, the information will still be available on the other drives. The overall performance will also improve since the reading and writing processes can be split between multiple drives, so a single one won't be overloaded. There're different sorts of RAIDs where the efficiency and fault tolerance may 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 then mirrored on another, the number of drives are used for the RAID, and so on.
RAID in Shared Hosting
The SSD drives which our cutting-edge cloud hosting platform uses for storage operate in RAID-Z. This type of RAID is created to work with the ZFS file system which runs on the platform and it employs the so-called parity disk - a specific drive where information located on the other drives is cloned with an additional bit added to it. If one of the disks stops working, your websites will continue working from the other ones and after we replace the faulty one, the info which will be copied on it will be rebuilt from what is stored on the remaining drives as well as the data from the parity disk. This is done so as to be able to recalculate the bits of each file correctly and to authenticate the integrity of the info cloned on the new drive. This is another level of security for the content that you upload to your shared hosting account in addition to the ZFS file system that analyzes a unique digital fingerprint for every single file on all the drives in real time.
RAID in Semi-dedicated Servers
The RAID type that we use for the cloud web hosting platform where your semi-dedicated server account shall be created is referred to as RAID-Z. What's different about it is that at least 1 of the disks is employed as a parity drive. Put simply, whenever any kind of data is duplicated on this specific disk drive, one more bit is included to it and if a problematic disk is replaced, the information which will be cloned on it is a mix of the data on the remaining hard disks in the RAID and that on the parity one. We do this to make sure that the information is intact. During this process, your sites will be up and running normally since RAID-Z makes it possible for a whole drive to fail without any service disturbances and it simply works by using one of the other ones as the main production drive. Employing RAID-Z together with the ZFS file system which uses checksums to warrant that no data will get silently corrupted on our servers, you won't ever need to worry about the integrity of your files.
RAID in VPS Servers
The SSD drives which we use on the physical machines where we create VPS servers function in RAID to ensure that any content that 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 cloned on it. If a main drive stops working, it is replaced and the information which will be duplicated on it is calculated between the remaining drives and the parity one. It's done this way to make sure that the right data is copied and that no file is corrupted because the new drive will be incorporated into the RAID afterwards. In addition, we use hard drives functioning in RAID on the backup servers, so in the event that you add this upgrade to your VPS plan, you'll use an even more reliable hosting service as your content will be available on multiple drives irrespective of any sort of unforeseen hardware malfunction.