NAS? RAID Technology? what is it?

What is NAS (Network attached storage) storage?

It is a centralized storage device used to store data from any device in your network. In simple terms, it is like an external hard drive but it is connected over the internet, unlike an external hard drive, which means, you can access, upload, and download, etc your files, documents, and any other data to the external hard drive over the internet from any part of the world, on any computer, all the time without the need to physically carry and connect them to your computer port each time you need them. Moreover, NAS storage is more than a simple storage solution. A NAS is a bay of hard drives put together in one box.

RAID Technology

Redundant Array of Independent Disk (RAID) technology is a technology used for data loss prevention from hard drives. In a RAID setup data is spread/ copied onto multiple hard disk so that in an event of a disk failure no data loss will occur. NAS uses RAID technology to configure the drives. NAS is typically connected directly to a router or a switch so other devices in the network can access it. There are commonly 4 types of RAID levels used.

Different levels of RAID:

RAID 0: It is a basic level which is not considered fault-tolerant as it has a high chance of data loss. In a RAID 0 setup, the data is not duplicated and is simply stored on multiple disks without any duplication so if one of the data or disk is corrupt then the entire data is lost.

RAID 1: RAID 1 is fault tolerant. In a RAID 1 setup, the data is copied in more than one disk creating redundancy (backup). For example, if there are two disk then two disk will be having same copies of data.

RAID 5: RAID 5 setup uses more disk drives than RAID 1 usually 3 or more and is the most common type of RAID setup used due to its speed and ability to store large amounts of data. In a RAID 5 setup the data is not duplicated across multiple disks instead it uses data striping and parity. Data striping is the technique of segmenting/ spreading the sequential data onto 3 or more hard disks, such as a file so that consecutive segments are stored on different physical storage devices in other words, data is split between multiple disks sequentially. For example if disk 1 contains file A then disk 2 will contain file B. Parity is used to rebuild data in the event of a disk failure, so if a disk failure were to happen in RAID 5 then the parity information stored in other drives will restore the data once the corrupt hard disk is replaced making it redundant. The demerit of RAID 5 technology is that only one hard disk failure can be handled and can use parity information to rebuilt the data but if more than two disk fails then the entire RAID 5 will shut down.

RAID 6: RAID 6 uses 4 or more drives/ disks and functions just like RAID 5 where the data is striped onto multiple disks along with parity information, however, the difference in RAID 6 is that the parity information is spread twice on all the hard disks unlike RAID 5 where parity is stored just once in every disk. The reason for storing parity twice in RAID 6 is that it can be capable of handling more than 1 disk failure and help rebuild data on those failed disks once it is replaced.

RAID 10: RAID 10 uses a combination of RAID 0 and RAID 1 where the data is duplicated/ copied onto multiple sets of disks using RAID 1 and these two sets of disks are then striped using RAID 0. RAID 10 uses a minimum if 4 hard disks which can then be used as two sets of disks which will be striped using RAID 0