Difference between hardware and software Raid

RAID stands for Redundant Array of Inexpensive Disks. This is a method of improving the performance and reliability of your storage media by using multiple drives. The drives are configured, so that the data is either divided between disks to distribute load, or duplicated to ensure thatit can be recovered once a disk fails. Both can also be implemented together, to obtain both benefits, although more drives will be used. Hardware RAID was the initial type of RAID available, where a specially built RAID controller handles the drives so that the processes are almost transparent to the host computer. Software RAID is a newer type of RAID where no specialized hardware is needed, and the host computer is responsible for the drives.

Obviously, hardware RAID is pricier compared to software RAID, due to the extra hardware that you needto purchase. The hardware is typically expensive, and adds a substantial amount to the cost of the whole system. On the flip side, the cheap software RAID can impair the host computer, which may result in poor performance. This is because it needs to process the databefore it is written to disk, to determine where each piece of data should go. The performance hit taken by the system can vary a lot, depending on what type of RAID array you have in use. It could be very minimal, as with the case of a JBOD array. Or it can be quite substantial, especially with stripping and mirroring on multiple disks. The controller in a hardware RAID handles these operations, so that the host processor does not have to. The host processor will simply write the data, just like in a normal hard drive.

Hardware RAID offers better reliability compared to software RAID. A software RAID can be prone to data corruption, due to the fault of the RAID software or driver that is being used. A software RAID can also be affected if the host computer is heavily loaded. Heavy processing can cause some pieces of data to be delayed by a small amount of time. These delays can add up, and negate the benefits of the RAID array to some degree.