RAID, or Redundant Array of Independent Disks, is a technology for keeping data on a number hard disks that function together as a single logical unit. The drives could be physical or logical i.e. in the second case one single drive is divided into separate ones through virtualization software. In either case, exactly the same information is saved on all of the drives and the key advantage of employing this type of a setup is that if a drive breaks down, the data will still be available on the other ones. Employing a RAID also boosts the performance because the input and output operations will be spread among a number of drives. There are several kinds of RAID based on how many hard disks are used, whether writing is carried out on all drives in real time or just on one, and how the data is synchronized between the hard drives - whether it is written in blocks on one drive after another or all of it is mirrored from one on the others. All of these factors indicate that the fault tolerance as well as the performance between the different RAID types could differ.
RAID in Website Hosting
Any content that you upload to your new website hosting account will be saved on fast SSD drives which work 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 protection for your website content in addition to the real-time checksum verification that ZFS uses to guarantee 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 info is written on it, an extra bit is added, so if any drive fails for whatever reason, the stability of the data can be verified by recalculating its bits based on what is stored on the production disks and on the parity one. With RAID-Z, the functioning of our system won't be interrupted and it will continue working flawlessly until the problematic drive is replaced and the info is synchronized on it.
RAID in Semi-dedicated Hosting
The information uploaded to any semi-dedicated hosting account is saved on SSD drives that function in RAID-Z. One of the drives in such a configuration is used for parity - any time data is copied on it, an additional bit is added. In case a disk happens to be defective, it will be taken out of the RAID without interrupting the functioning of the websites because the data will load from the remaining drives, and when a brand new drive is included, the data which will be duplicated on it will be a mix between the info on the parity disk and data kept on the other hard disks in the RAID. This is done so as to ensure that the information which is being copied is accurate, so as soon as the new drive is rebuilt, it could be included in the RAID as a production one. This is one more warranty for the integrity of your data since the ZFS file system which runs on our cloud hosting platform analyzes a special checksum of all of the copies of the files on the separate drives to be able to avoid any possibility of silent data corruption.
The SSD drives which we use on the machines where we set up virtual private servers work in RAID to ensure that any content which you upload will be available and intact all the time. At least 1 drive is used for parity - one bit of info is added to any data cloned on it. In case a main drive breaks down, it is replaced and the information which will be copied on it is calculated between the remaining drives and the parity one. This is done to make sure that the needed data is copied and that no file is corrupted as the new drive will be used in the RAID afterwards. In addition, we use hard disks functioning in RAID on the backup servers, so if you add this upgrade to your VPS package, you will use an even more reliable web hosting service because your content will be available on multiple drives regardless of any sort of unpredicted hardware failure.