Hardware RAID is a form of RAID (redundant array of independent disks) where processing is done on the motherboard or a separate RAID card.
RAID spreads data on multiple hard disks, balancing overlapping I/O operations. This improves performance and increases the mean time between failures, increasing fault tolerance. RAID can be in the format of a hardware or software system.
With hardware RAID, logical disks are configured and mirrored outside of the system. A physical controller manages the array, presenting data to applications and operating systems as logical units. The controller resides on a PCI bus.
The difference in hardware RAID and software RAID is where the RAID processing happens. Software RAID performs the processing on the host’s CPU. Because it does not use the server processor, hardware RAID provides better performance. However, because of the need for additional hardware, it is more expensive than software RAID.