RAID, or Redundant Array of Independent Disks, is a technology of saving data on several hard disk drives that function together as one single logical unit. The drives could be physical or logical i.e. in the latter case one drive is split into individual ones through virtualization software. In either case, the same data is saved on all of the drives and the main benefit of using this type of a setup is that in case a drive breaks down, the data shall still be available on the remaining ones. Employing a RAID also boosts the overall performance as the input and output operations will be spread among a couple of drives. There are several types of RAID depending on how many hard drives are used, whether writing is performed on all the drives in real time or just on a single one, and how the info is synced between the hard drives - whether it's recorded in blocks on one drive after another or it is mirrored from one on the others. These factors show that the fault tolerance and the performance between the different RAID types could differ.
RAID in Shared Web Hosting
The SSD drives which our cutting-edge cloud hosting platform employs for storage operate in RAID-Z. This type of RAID is developed to work with the ZFS file system that runs on the platform and it takes advantage of the so-called parity disk - a special drive where data kept on the other drives is copied with an additional bit added to it. In case one of the disks stops working, your websites shall continue working from the other ones and after we replace the bad one, the data that will be cloned on it will be rebuilt from what is stored on the rest of the drives as well as the information from the parity disk. This is done in order to be able to recalculate the bits of every file properly and to verify the integrity of the info duplicated on the new drive. This is one more level of security for the content that you upload to your shared web hosting account together with the ZFS file system that compares a special digital fingerprint for each file on all the drives in real time.
RAID in Semi-dedicated Hosting
The information uploaded to any semi-dedicated hosting account is kept on SSD drives which operate in RAID-Z. One of the drives in type of a setup is used for parity - whenever data is copied on it, an additional bit is added. If a disk happens to be flawed, it will be removed from the RAID without interrupting the work of the sites as the data will load from the other drives, and when a new drive is included, the information that will be cloned on it will be a mix between the information on the parity disk and data stored on the other hard drives in the RAID. This is done in order to ensure that the information that is being copied is correct, so once the new drive is rebuilt, it can be incorporated into the RAID as a production one. This is an additional warranty for the integrity of your information since the ZFS file system that runs on our cloud Internet hosting platform analyzes a unique checksum of all copies of the files on the various drives so as to avoid any chance of silent data corruption.
RAID in VPS Hosting
The SSD drives which we use on the physical machines where we set up virtual private servers work in RAID to make sure that any content which you upload will be available and intact all of the time. At least 1 drive is employed for parity - one bit of info is added to any data copied on it. If a main drive stops working, it is changed and the information that will be cloned on it is calculated between the rest of the drives and the parity one. It's done this way to make sure that the correct data is copied and that not a single file is corrupted since the new drive will be used in the RAID afterwards. In addition, we use hard drives functioning in RAID on the backup servers, so in case you add this upgrade to your VPS plan, you will use an even more reliable hosting service since your content will be available on multiple drives regardless of any sort of unforeseen hardware failure.