RAID, or Redundant Array of Independent Disks, is a technology for keeping data on several hard drives which function together as one logical unit. The drives could be physical or logical i.e. in the latter case one single drive is split into separate ones through virtualization software. Either way, exactly the same information is saved on all the drives and the main advantage of employing such a setup is that in case a drive stops working, the data shall still be available on the remaining ones. Employing a RAID also boosts the overall 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 performed on all the drives in real time or just on a single one, and how the info is synchronized between the drives - whether it's written in blocks on one drive after another or all of it is mirrored from one on the others. All these factors imply that the error tolerance and the performance between the various RAID types may differ.
RAID in Shared Hosting
The state-of-the-art cloud web hosting platform where all shared hosting accounts are generated uses quick SSD drives as an alternative to the classic HDDs, and they operate in RAID-Z. With this setup, multiple hard disks operate together and at least one is a dedicated parity disk. Simply put, when data is written on the other drives, it's cloned on the parity one adding an extra bit. This is carried out for redundancy as even if a drive fails or falls out of the RAID for whatever reason, the info can be rebuilt and verified using the parity disk and the data recorded on the other ones, thus not a thing will be lost and there will not be any service disturbances. This is one more level of protection for your info along with the cutting-edge ZFS file system that uses checksums to make sure that all data on our servers is undamaged and is not silently corrupted.
RAID in Semi-dedicated Hosting
In case you host your sites in a semi-dedicated hosting account from our company, all of the content that you upload will be held on SSD drives which work in RAID-Z. With this kind of RAID, at least 1 of the drives is used for parity - when data is synchronized between the drives, an extra bit is added to it on the parity one. The purpose behind this is to guarantee the integrity of the information which is cloned to a brand new drive if one of the disks in the RAID stops functioning because the content being copied on the brand new disk is recalculated from the info on the standard hard drives and on the parity one. Another advantage of RAID-Z is that even in case a drive stops working, the system can easily switch to a different one instantly without service disruptions of any kind. RAID-Z adds one more level of safety for the content that you upload on our cloud hosting platform together with the ZFS file system which uses unique checksums to verify the integrity of each and every file.
RAID in VPS Web Hosting
The SSD drives which we use on the machines where we create virtual private servers work in RAID to ensure that any content that you upload will be available and intact at all times. At least 1 drive is used for parity - one bit of information is added to any data cloned on it. In the event that a main drive fails, it is replaced and the info which will be copied on it is calculated between the other 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 a part of the RAID afterwards. In addition, we use hard drives working 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 because your content will be available on multiple drives regardless of any sort of unforeseen hardware failure.