RAID, or Redundant Array of Independent Disks, is a technology of storing data on several hard disks which work together as one single logical unit. The drives could be physical or logical i.e. in the latter case one single drive is split into separate ones using virtualization software. In either case, the same data is kept on all the drives and the key benefit of using this kind of a setup is that in the event that a drive fails, the data will still be available on the remaining ones. Using a RAID also improves the performance since the input and output operations will be spread among a few drives. There are several types of RAID based on how many hard drives are used, whether writing is done on all drives in real time or just on one, and how the info is synchronized between the hard 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 fault tolerance as well as the performance between the various RAID types can differ.
RAID in Shared Hosting
The SSD drives which our cutting-edge cloud hosting platform employs 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 employs the so-called parity disk - a specific drive where data saved on the other drives is cloned with an extra bit added to it. In the event that one of the disks stops working, your sites will continue working from the other ones and as soon as we replace the faulty one, the info that will be copied on it will be recovered from what is stored on the remaining drives together with the information from the parity disk. This is performed so as to be able to recalculate the bits of each and every file correctly and to validate the integrity of the information duplicated on the new drive. This is an additional level of security for the info which you upload to your shared hosting account together with the ZFS file system that analyzes a unique digital fingerprint for each and every file on all drives in real time.
RAID in Semi-dedicated Hosting
The information uploaded to any semi-dedicated hosting account is saved on SSD drives that work in RAID-Z. One of the drives in this kind of a setup is used for parity - any time data is cloned on it, an extra bit is added. In case a disk turns out to be faulty, it will be taken out of the RAID without interrupting the operation of the websites as the data will load from the remaining drives, and when a new drive is added, the data which will be copied on it will be a mix between the info on the parity disk and data kept on the other hard drives in the RAID. That is done to guarantee that the info which 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 extra warranty for the integrity of your information because the ZFS file system that runs on our cloud web hosting platform compares a special checksum of all the copies of your files on the separate drives to be able to avoid any probability of silent data corruption.
In case you employ one of our virtual private server packages, any content you upload will be stored on SSD drives that operate in RAID. At least a single drive is employed for parity so as to guarantee the integrity of your info. In simple terms, this is a special drive where data is copied with one bit added to it. In the event that a disk part of the RAID breaks down, your Internet sites will continue working and when a new disk replaces the defective one, the bits of the info that will be duplicated on it are calculated using the healthy and the parity drives. This way, any potential for corrupting data during the process is prevented. We also employ standard hard disk drives which work in RAID for storing backups, so in case you add this service to your VPS package, your content will be stored on multiple drives and you'll never have to worry about its integrity even in the event of multiple drive failures.