What is a RAID Controller?

What is a RAID Controller?

RAID Controller, also known as disk array controller, is a hardware device that manages the physical disk drives and presents them to a server or system as logical drives. In other words, RAID controller a device that enables communication between the server operating system and the disk drives. RAID controller essentially provides this communication for data redundancy or to improve the performance of the hard drives. The front end of a RAID controller communicates with the server usually via HBA (Host Bus Adapter) and the back end of the RAID controller communicates and manages the disk drives.

Key Advantages of using a RAID Controller

• RAID adapter enables you to manage disk drives and RAID configuration independently from the Operating System. The RAID card does not take away processing power from the disks it manages or the operating system or the server, hence more speed to read and write data.
• Protects against data loss or corruption that may occur to the hard drives – for example: should there be a sudden power loss. Most RAID cards have cache (buffer) and/or battery which also adds to the speed as well as data loss.

Features to consider when purchasing a RAID Controller

• SATA and/or SAS interface (and related throughput speeds)
• RAID levels supported
• Operating system compatibility
• Number of devices supported
• Read/write performance
• IOPs rating
• Cache size
• PCI-e interface (PCI, PCI-e, PCI-X)
• Encryption capabilities
• Power consumption
• Drive Capacity Compatibility (Some raid cards have a limit to the physical size of hard drive it may support). For Example: Dell H700 RAID Controller can support drives more than 2TB Capacity.
• Cabling (make sure you have all the necessary cables to install the card)