RAID, which stands short for Redundant Array of Independent Disks, is a software or hardware storage virtualization technology which permits a system to use multiple hard drives as a single logical unit. Simply put, all of the drives are used as one and the info on all of them is the same. Such a setup has 2 key advantages over using just a single drive to store data - the first one is redundancy, so in case one drive fails, the information will be accessible from the others, and the second one is better performance as the input/output, or reading/writing operations will be spread among different drives. You can find different RAID types in accordance with how many drives are employed, if reading and writing are both handled from all of the drives at the same time, if data is written in blocks on one drive after another or is mirrored between drives in the same time, etc. Based on the particular setup, the fault tolerance and the performance may vary.
RAID in Shared Hosting
The drives which we employ for storage with our state-of-the-art cloud hosting platform are not the traditional HDDs, but quick solid-state drives (SSD). They function in RAID-Z - a special setup intended for the ZFS file system which we employ. All the content that you upload to your shared hosting account will be kept on multiple hard disks and at least 1 shall be used as a parity disk. This is a special drive where an additional bit is included to any content copied on it. In case a disk in the RAID stops working, it'll be replaced with no service disturbances and the data will be rebuilt on the new drive by recalculating its bits thanks to the data on the parity disk along with that on the remaining disks. This is done so as to guarantee the integrity of the information and together with the real-time checksum verification that the ZFS file system performs on all drives, you won't ever need to concern yourself with the loss of any info no matter what.
RAID in Semi-dedicated Servers
The SSD drives that are used for storing any content uploaded to the semi-dedicated server accounts that we offer function in RAID-Z. This is a specific setup where one or more hard drives are employed for parity i.e. the system will include an extra bit to any data cloned on this type of a drive. In the event that a disk fails and is substituted with a new one, what information will be cloned on the latter shall be a combination calculated between the data on the remaining disks and that on the parity one. This is done to ensure that the data on the new drive shall be correct. During the process, the RAID will continue functioning normally and the problematic drive won't have an effect on the normal operation of your sites by any means. Using SSDs in RAID-Z is a superb addition to the ZFS file system which runs on our state-of-the-art cloud platform in terms of preserving the integrity of your files as ZFS uses specific digital identifiers named checksums to avoid silent data corruption.
RAID in VPS Servers
All VPS server accounts that our company provides are created on physical servers that use SSD drives working in RAID. At least 1 drive is used for parity - one extra bit is added to the information cloned on it and in case a main disk stops working, this bit makes it much simpler to recalculate the bits of the files on the failed disk drive so that the accurate information is restored on the new drive included in the RAID. Meanwhile, your websites will stay online as all the data will still load from at least 1 other hard disk. If you add routine backups to your VPS plan, a copy of your info will be kept on standard hard drives which also operate in RAID because we would like to make sure that any site content you upload will be safe and sound at all times. Employing multiple hard drives in RAID for all the main and backup servers enables us to offer fast and reliable web hosting service.