RAID, or Redundant Array of Independent Disks, is a technology for storing data on several hard disks that function together as a single logical unit. The drives can be physical or logical i.e. in the latter case a single drive is divided into separate ones through virtualization software. In either case, identical data is saved on all drives and the basic advantage of using such a setup is that if a drive stops working, the data will remain available on the other ones. Employing a RAID also improves the overall performance since the input and output operations will be spread among a few drives. There are several kinds of RAID depending on how many drives are used, whether writing is performed on all drives in real time or just on one, and how the data is synced between the hard drives - whether it is written in blocks on one drive after another or it is mirrored from one on the others. All these factors show that the error tolerance as well as the performance between the different RAID types can vary.
RAID in Shared Website Hosting
Any content which you upload to your new shared website hosting
account will be saved on quick SSD drives that operate in RAID-Z. This configuration is built to use the ZFS file system that runs on our cloud Internet hosting platform and it adds an additional level of protection for your website content in addition to the real-time checksum validation which ZFS uses to guarantee the integrity of the data. With RAID-Z, the data is stored on a number of disks and at least one of them is a parity disk - whenever info is recorded on it, an extra bit is added, so in the event that any drive stops working for whatever reason, the integrity of the info can be verified by recalculating its bits based on what is kept on the production hard drives and on the parity one. With RAID-Z, the operation of our system will not be interrupted and it'll continue operating effectively until the faulty drive is changed and the data is synchronized on it.
RAID in Semi-dedicated Servers
The data uploaded to any semi-dedicated server
account is stored on SSD drives which work in RAID-Z. One of the drives in this kind of a setup is used for parity - whenever data is cloned on it, an additional bit is added. In case a disk turns out to be defective, it will be taken out of the RAID without disturbing the operation of the Internet sites since the data will load from the other drives, and when a new drive is included, the data that will be copied on it will be a mix between the data on the parity disk and data saved on the other hard drives in the RAID. This is done to guarantee that the info which is being duplicated is accurate, so once the new drive is rebuilt, it can be incorporated into the RAID as a production one. This is an additional warranty for the integrity of your data since the ZFS file system which runs on our cloud Internet hosting platform analyzes a unique checksum of all copies of the files on the separate drives in order to avoid any chance of silent data corruption.
RAID in VPS Servers
The SSD drives that we use on the machines where we create VPS servers
function in RAID to ensure that any content you upload will be available and intact all the time. At least one drive is employed for parity - one bit of data is added to any data cloned on it. If a main drive breaks down, it is replaced and the information which will be cloned on it is calculated between the rest of the drives and the parity one. That’s done to make sure that the correct data is copied and that not a single file is corrupted as the new drive will be included in the RAID afterwards. Also, we use hard disks operating in RAID on the backup servers, so if you add this upgrade to your VPS package, you will use an even more reliable web hosting service because your content will be available on multiple drives irrespective of any type of unexpected hardware malfunction.