RAID, or Redundant Array of Independent Disks, is a technology for saving data on several hard disk drives which operate together as a single logical unit. The drives could be physical or logical i.e. in the latter case a single drive is split into independent ones through virtualization software. In any case, the very same info is saved on all the drives and the main benefit of using such a setup is that in case a drive fails, the data shall still be available on the remaining ones. Employing a RAID also boosts the performance since the input and output operations will be spread among a few drives. There are several kinds of RAID depending on how many drives are used, whether writing is done on all of the drives in real time or just on one, and how the information is synced between the drives - whether it's written in blocks on one drive after another or it is mirrored from one on the others. These factors mean that the error tolerance as well as the performance between the different RAID types can vary.
RAID in Cloud Website Hosting
The hard disks which we use for storage with our top-notch cloud web hosting platform are not the classic HDDs, but super fast solid-state drives (SSD). They work in RAID-Z - a special setup developed for the ZFS file system which we employ. All the content that you upload to the cloud website hosting account will be kept on multiple drives and at least one will be used as a parity disk. This is a special drive where a further bit is included to any content copied on it. In case a disk in the RAID stops functioning, it'll be changed without service disturbances and the information will be rebuilt on the new drive by recalculating its bits using the data on the parity disk plus that on the remaining disks. This is done to guarantee the integrity of the info and along with the real-time checksum validation which the ZFS file system performs on all drives, you will never have to be concerned about the loss of any data no matter what.
RAID in Semi-dedicated Servers
The RAID type that we employ for the cloud Internet hosting platform where your semi-dedicated server account will be created is called RAID-Z. What's different about it is that at least one of the disks is employed as a parity drive. In simple terms, whenever any data is copied on this specific drive, one more bit is added to it and in case a faulty disk is changed, 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. This is done to ensure that your data is intact. Throughout this process, your sites will be working normally since RAID-Z allows for a whole drive to fail without causing any service disturbances and it simply uses one of the other ones as the main production drive. Using RAID-Z together with the ZFS file system that uses checksums to guarantee that no data shall get silently corrupted on our servers, you won't ever have to worry about the integrity of your files.