RAID, or Redundant Array of Independent Disks, is a technology for storing data on several hard drives which operate together as one single logical unit. The drives can be physical or logical i.e. in the latter case one drive is split into individual ones via virtualization software. Either way, exactly the same information is stored on all of the drives and the basic advantage of employing this kind of a setup is that in the event that a drive breaks down, the data will still be available on the other ones. Having a RAID also enhances the performance since the input and output operations will be spread among several drives. There are several types of RAID based on how many hard disks are used, whether writing is done on all the drives in real time or just on a single one, and how the information is synced between the hard drives - whether it is recorded in blocks on one drive after another or it is mirrored from one on the others. All of these factors indicate that the error tolerance and the performance between the various RAID types may differ.
RAID in Shared Hosting
The drives which we employ for storage with our innovative cloud web hosting platform are not the traditional HDDs, but super fast solid-state drives (SSD). They work in RAID-Z - a special setup developed for the ZFS file system which we use. All of the content that you upload to your shared hosting account will be held on multiple disk drives and at least one of them will be used 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 stops functioning, it'll be changed without service interruptions and the information will be recovered on the new drive by recalculating its bits thanks to the data on the parity disk along with that on the other disks. This is done in order to guarantee the integrity of the information and along with the real-time checksum verification which the ZFS file system performs on all drives, you will never have to be concerned about losing any information no matter what.
RAID in Semi-dedicated Hosting
If you host your websites in a semi-dedicated hosting account from our company, all the content you upload will be held on SSD drives which operate in RAID-Z. With this form of RAID, at least 1 of the hard disks is employed for parity - when data is synchronized between the disks, an additional bit is added to it on the parity one. The purpose behind this is to ensure the integrity of the information that is copied to a new drive in case one of the drives in the RAID stops functioning as the site content being copied on the new disk is recalculated from the info on the standard disk drives and on the parity one. An additional advantage of RAID-Z is the fact that even in case a hard drive fails, the system could switch to a different one quickly without service disruptions of any kind. RAID-Z adds one more level of safety for the content which you upload on our cloud Internet hosting platform together with the ZFS file system which uses unique checksums to verify the integrity of every single file.