Redundant Array of Independent Disks, or RAID, is a method of keeping content on multiple hard disks concurrently. A RAID could be software or hardware based on the drives that are used - physical or logical ones, however what is common between them is that they all perform as just one single unit where info is kept. The biggest advantage of using a RAID is redundancy as the data on all the drives shall be the same at all times, so even in the event that a drive fails for whatever reason, the data will still be available on the rest of the drives. The overall performance is also better since the reading and writing processes will be split between multiple drives, so a single one won't be overloaded. There are different kinds of RAIDs where the efficiency and fault tolerance could differ based on the exact setup - whether data is written on all the drives real-time or it's written on a single drive and afterwards mirrored on another, what amount of drives are used for the RAID, etcetera.
RAID in Shared Hosting
The hard drives which we use for storage with our ground-breaking cloud hosting platform are not the classic HDDs, but extremely fast solid-state drives (SSD). They function in RAID-Z - a special setup intended for the ZFS file system that we use. Any content that you upload to your shared hosting account will be held on multiple disk drives and at least one of them will 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 will be changed without any service disturbances and the info will be recovered on the new drive by recalculating its bits using the data on the parity disk along with that on the other disks. This is done so as to guarantee the integrity of the data and together with the real-time checksum authentication which the ZFS file system executes on all drives, you will never need to concern yourself with the loss of any info no matter what.
RAID in Semi-dedicated Hosting
In case you host your websites in a semi-dedicated hosting account from our firm, any content that you upload will be kept on SSD drives which work in RAID-Z. With this form of RAID, at least 1 of the hard disks is employed for parity - when data is synchronized between the hard drives, an additional bit is added to it on the parity one. The purpose behind this is to ensure the integrity of the info that is cloned to a new drive if one of the disks in the RAID breaks down because the content being copied on the new disk is recalculated from the information on the standard disk drives and on the parity one. Another advantage of RAID-Z is that even in case a drive fails, the system can easily switch to another one immediately without service interruptions of any kind. RAID-Z adds an extra level of safety for the content which you upload on our cloud hosting platform in addition to the ZFS file system that uses unique checksums to verify the integrity of every single file.