Redundant Array of Independent Disks, or RAID, is a method of saving content on multiple hard disk drives simultaneously. A RAID might be software or hardware depending on the HDDs that are used - physical or logical ones, still what’s common between them is that they all operate as a single unit where information is kept. The biggest advantage of employing a RAID is redundancy because the info on all the drives is the same all of the time, so even in case a drive fails for whatever reason, the information will still be present on the remaining drives. The general performance is also enhanced since the reading and writing processes will be split between different drives, so a single one can't be overloaded. There're different kinds of RAIDs where the functionality and fault tolerance can vary depending on the specific setup - whether data is written on all the drives in real time or it is written on one drive and afterwards mirrored on another, what number of drives are used for the RAID, etc.
RAID in Website Hosting
All content that you upload to your new website hosting account will be saved on fast SSD drives that operate in RAID-Z. This configuration is built to use the ZFS file system that runs on our cloud hosting platform and it adds one more level of security for your site content on top of the real-time checksum authentication that ZFS uses to ensure the integrity of the data. With RAID-Z, the info is saved on a couple of disks and at least one is a parity disk - whenever data is written on it, an extra bit is added, so if any drive stops functioning for some reason, the integrity of the information can be verified by recalculating its bits based on what is stored on the production hard drives and on the parity one. With RAID-Z, the functioning of our system will not be interrupted and it will continue functioning flawlessly until the problematic drive is changed and the info is synced on it.