Redundant Array of Independent Disks, or RAID, is a way of keeping content on multiple hard drives concurrently. A RAID could 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 perform as just one single unit where your information is kept. The key advantage of employing a RAID is redundancy because the info on all drives shall be identical at all times, so even in the event that a drive fails for whatever reason, the data will still be present on the remaining drives. The overall performance will also improve because the reading and writing processes will be split between a number of drives, so a single one won't be overloaded. There're different kinds of RAIDs where the performance and fault tolerance may vary according to the particular setup - whether info is written on all drives in real time or it's written on a single drive and afterwards mirrored on another, what number of drives are used for the RAID, and so on.
RAID in Shared Hosting
The state-of-the-art cloud web hosting platform where all shared hosting accounts are created uses fast SSD drives as opposed to the standard HDDs, and they operate in RAID-Z. With this setup, multiple hard disks function together and at least a single one is a dedicated parity disk. In simple terms, when data is written on the remaining drives, it is duplicated on the parity one adding an extra bit. This is done for redundancy as even if a drive fails or falls out of the RAID for whatever reason, the information can be rebuilt and verified using the parity disk and the data saved on the other ones, so nothing will be lost and there will be no service interruptions. This is one more level of protection for your info together with the advanced ZFS file system which uses checksums to ensure that all data on our servers is intact and is not silently corrupted.
RAID in Semi-dedicated Hosting
In case you host your sites in a semi-dedicated hosting account from our company, any content that you upload will be kept on SSD drives which work in RAID-Z. With this type of RAID, at least one of the drives is used for parity - when data is synced between the drives, an extra bit is included in it on the parity one. The idea behind this is to guarantee the integrity of the information which is copied to a new drive in case one of the disks in the RAID stops functioning as the content being copied on the brand new disk is recalculated from the data on the standard disk drives and on the parity one. Another advantage of RAID-Z is the fact that even in the event that a disk drive stops working, the system can easily switch to another one right away without service interruptions of any type. RAID-Z adds an extra level of protection for the content that you upload on our cloud Internet hosting platform in addition to the ZFS file system that uses unique checksums as a way to validate the integrity of every single file.
The SSD drives that we use on the machines where we create virtual private servers function in RAID to ensure that any content that you upload will be available and intact all the time. At least a single drive is employed for parity - one bit of info is added to any data cloned on it. If a main drive fails, it is changed and the information that will be cloned on it is calculated between the remaining drives and the parity one. That’s done to ensure that the needed information is copied and that not a single file is corrupted because the new drive will be incorporated into the RAID afterwards. In addition, we use hard disks operating 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 Internet hosting service because your content will be available on multiple drives regardless of any kind of sudden hardware failure.