Redundant Array of Independent Disks, or RAID, is a way of saving content on a number of hard disks concurrently. A RAID might be software or hardware based on the hard drives which are used - physical or logical ones, however what is common between them is that they all work as just a single unit where info is kept. The biggest advantage of employing a RAID is redundancy because the information on all of the drives is identical all the time, so even in case a drive fails for some reason, the info will still be available on the other drives. The overall performance will also improve since the reading and writing processes could be split between multiple drives, so a single one will never be overloaded. There're different sorts of RAIDs where the performance and fault tolerance may differ based on the exact setup - whether your data is written on all the drives in real time or it's written on a single drive and then mirrored on another, what amount of drives are used for the RAID, etc.
RAID in Shared Hosting
The disk drives that we use for storage with our innovative cloud web hosting platform are not the traditional HDDs, but fast solid-state drives (SSD). They work in RAID-Z - a special setup developed for the ZFS file system that we employ. Any content that you add to your shared hosting account will be stored on multiple hard drives and at least one shall be employed as a parity disk. This is a specific drive where an extra bit is added to any content copied on it. In case a disk in the RAID fails, it'll be replaced with no service interruptions and the info will be recovered on the new drive by recalculating its bits using the data on the parity disk plus that on the remaining disks. This is done in order to ensure the integrity of the information and along with the real-time checksum authentication which the ZFS file system performs on all drives, you will never need to concern yourself with the loss of any info no matter what.
RAID in Semi-dedicated Servers
The SSD drives that are used for storing any website content uploaded to the semi-dedicated server accounts which we offer work in RAID-Z. This is a special setup where one or more hard drives are employed for parity i.e. the system will add an extra bit to any data duplicated on this type of a hard drive. If a disk fails and is substituted with a new one, what data will be cloned on the latter shall be a combination calculated between the data on the other drives and that on the parity one. This is done to ensure that the information on the new drive shall be accurate. During the process, the RAID will continue operating normally and the faulty drive will not impact the normal operation of your websites by any means. Using SSDs in RAID-Z is a great addition to the ZFS file system which runs on our state-of-the-art cloud platform with regards to preserving the integrity of your files because ZFS uses specific digital identifiers identified as checksums in order to avoid silent data corruption.
RAID in VPS Servers
The physical servers where we create VPS server work with extremely fast SSD drives that will increase the speed of your websites substantially. The hard disks function in RAID to make sure that you will not lose any data as a result of a power loss or a hardware failure. The production servers employ many different drives where the info is kept and one disk is used for parity i.e. one bit is added to all of the info copied on it, which makes it much easier to restore the website content without loss if a main drive breaks down. In case you take advantage of our backup service, the info will be stored on an individual machine which uses standard hard-disk drives and although there is no parity one in this case, they are also in a RAID to ensure that we will have a backup copy of your site content at all times. With this type of setup your info will always be safe as it will be available on many drives.