RAID, or Redundant Array of Independent Disks, is a technology for saving data on a number hard disks which work together as a single logical unit. The drives could be physical or logical i.e. in the latter case one drive is split into individual ones using virtualization software. Either way, the very same info 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 stops working, the data will remain available on the other ones. Employing a RAID also enhances the overall performance since the input and output operations will be spread among a couple of drives. There are several types of RAID depending 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 synchronized between the drives - whether it is recorded in blocks on one drive after another or it is mirrored from one on the others. All these factors suggest that the error tolerance and the performance between the various RAID types can differ.
RAID in Shared Web Hosting
The SSD drives that our cutting-edge cloud web hosting platform uses for storage function in RAID-Z. This type of RAID is intended to work with the ZFS file system which runs on the platform and it uses the so-called parity disk - a special drive where info saved on the other drives is cloned with an extra bit added to it. In case one of the disks stops functioning, your Internet sites will continue working from the other ones and as soon as we replace the malfunctioning one, the data that will be cloned on it will be recovered from what is stored on the other drives as well as the info from the parity disk. This is performed so as to be able to recalculate the bits of every single file correctly and to confirm the integrity of the information copied on the new drive. This is another level of security for the content which you upload to your shared web hosting account in addition to the ZFS file system which compares a special digital fingerprint for every single file on all the hard drives in real time.
RAID in Semi-dedicated Servers
The info uploaded to any semi-dedicated server account is stored on SSD drives which operate in RAID-Z. One of the drives in this kind of a configuration is used for parity - whenever data is copied on it, an extra bit is added. In case a disk turns out to be defective, it will be taken out of the RAID without interrupting the work of the sites as the data will load from the other drives, and when a brand new drive is added, the info which will be cloned on it will be a combination between the data on the parity disk and data stored on the other drives in the RAID. This is done in order to ensure that the information that is being cloned is accurate, so as soon as the new drive is rebuilt, it can be included in the RAID as a production one. This is an extra warranty for the integrity of your info since the ZFS file system which runs on our cloud web hosting platform compares a unique checksum of all the copies of the files on the separate drives to be able to avoid any chance of silent data corruption.
RAID in VPS Servers
The physical servers where we make VPS server work with high-speed SSD drives which will increase the speed of your websites significantly. The hard disks operate in RAID to make sure that you will not lose any info as a result of a power loss or a hardware failure. The production servers take advantage of multiple drives where the data 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 content without loss in the event a main drive stops working. If you use our backup service, the information will be saved on an individual machine that uses standard hard-disk drives and although there's no parity one in this case, they are also in a RAID to guarantee that we will have a backup of your content all of the time. With this type of configuration your info will always be safe because it will be available on a lot of disk drives.