RAID, or Redundant Array of Independent Disks, is a technology for storing data on a number hard disk drives which operate together as one single logical unit. The drives could be physical or logical i.e. in the latter case one single drive is split into different ones through virtualization software. In either case, identical information is saved on all of the drives and the basic advantage of using this kind of a setup is that in case a drive stops working, the data shall still be available on the other ones. Having a RAID also enhances the performance since the input and output operations will be spread among a couple of drives. There are several kinds of RAID based on how many drives are used, whether writing is performed on all drives in real time or just on a single 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 show that the fault tolerance as well as the performance between the various RAID types may vary.

RAID in Web Hosting

The drives which we employ for storage with our innovative cloud web hosting platform are not the traditional HDDs, but extremely fast solid-state drives (SSD). They operate in RAID-Z - a special setup created for the ZFS file system which we use. All of the content that you add to your web hosting account will be saved on multiple hard drives and at least 1 will be employed as a parity disk. This is a special drive where a further bit is added to any content copied on it. In case a disk in the RAID stops working, it will be replaced with no service disturbances and the data 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 so as to guarantee the integrity of the information and together with the real-time checksum validation which the ZFS file system runs on all drives, you will never need to worry about losing any info no matter what.

RAID in Semi-dedicated Hosting

The data uploaded to any semi-dedicated hosting account is kept on SSD drives that operate in RAID-Z. One of the drives in such a configuration is used for parity - every time data is copied on it, an extra bit is added. If a disk turns out to be problematic, it will be removed from the RAID without interrupting the operation of the websites as the data will load from the rest of the drives, and when a new drive is included, the information which will be duplicated on it will be a combination between the information on the parity disk and data stored on the other hard drives in the RAID. That is done to guarantee that the info which is being cloned is correct, so once the new drive is rebuilt, it could be incorporated into the RAID as a production one. This is an additional guarantee for the integrity of your data as the ZFS file system that runs on our cloud web hosting platform compares a special checksum of all copies of the files on the different drives to be able to avoid any probability of silent data corruption.