RAID, or Redundant Array of Independent Disks, is a technology for saving data on several hard disks which function together as a single logical unit. The drives could be physical or logical i.e. in the aforementioned case one single drive is divided into separate ones via virtualization software. In any case, the same information is saved on all the drives and the basic benefit of using such a setup is that if a drive breaks down, the data shall still be available on the other ones. Using a RAID also improves the performance because the input and output operations will be spread among a few drives. There are several types of RAID dependant upon how many drives 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 hard drives - whether it's recorded in blocks on one drive after another or it is mirrored from one on the others. All of these factors imply that the error tolerance as well as the performance between the various RAID types may vary.
RAID in Cloud Hosting
The SSD drives that our cutting-edge cloud hosting platform employs for storage function in RAID-Z. This kind of RAID is designed to work with the ZFS file system which runs on the platform and it uses the so-called parity disk - a specific drive where data saved on the other drives is copied with an additional bit added to it. In case one of the disks stops functioning, your websites will continue working from the other ones and as soon as we replace the bad one, the data that will be copied on it will be rebuilt from what is stored on the remaining drives along with the information from the parity disk. This is done in order to be able to recalculate the elements of each and every file adequately and to validate the integrity of the data cloned on the new drive. This is another level of security for the info which you upload to your cloud hosting account in addition to the ZFS file system which compares a unique digital fingerprint for every single file on all disk drives in real time.
RAID in Semi-dedicated Servers
The information uploaded to any semi-dedicated server account is stored on SSD drives that work in RAID-Z. One of the drives in such a setup is used for parity - each time data is cloned on it, an additional bit is added. In case a disk happens to be faulty, it will be taken out of the RAID without interrupting the operation of the Internet sites because the data will load from the remaining drives, and when a brand new drive is included, the info which will be duplicated on it will be a mix between the information on the parity disk and data stored on the other hard disks in the RAID. That is done so as to ensure that the data that is being copied is correct, so once the new drive is rebuilt, it can be included in the RAID as a production one. This is an additional warranty for the integrity of your data as the ZFS file system which runs on our cloud web hosting platform analyzes a special checksum of all the copies of your files on the separate drives to avoid any chance of silent data corruption.
RAID in VPS Servers
The SSD drives which we use on the physical machines where we create VPS servers work in RAID to make sure that any content which you upload will be available and intact at all times. At least a single drive is employed for parity - one bit of data is added to any data cloned on it. In case a main drive fails, it is changed and the info that will be cloned on it is calculated between the rest of the drives and the parity one. This is done to ensure that the correct information is copied and that no file is corrupted as the new drive will be incorporated into the RAID afterwards. In addition, we use hard drives operating in RAID on the backup servers, so if you add this upgrade to your VPS plan, you'll use an even more reliable web hosting service because your content will be available on multiple drives regardless of any type of unexpected hardware malfunction.