What is the HBA card What is the role of the HBA card?

HBA, that is, the host bus adapter English “ Host Bus Adapter & rdquo; abbreviation. A circuit board and/or integrated circuit adapter that enables a computer to provide input/output (I/O) processing and physical connections between servers and storage devices. A Host Bus Adapter (HBA) is a circuit board and/or integrated circuit adapter that provides input/output (I/O) processing and physical connectivity between servers and storage devices. Because the HBA eases the burden on the main processor in data storage and retrieval tasks, it can improve server performance. An HBA and its associated disk subsystem are sometimes referred to together as a disk channel.

We know that NICs are used to connect computers and computer networks. The network card is generally inserted in the large bus expansion slot of the computer, and the card has an interface connected to the computer network. The network card is physically connected to a computer internal bus, such as PCI, PCI-X, PCI-E, SUN's Sbus bus, etc., and a computer network such as Ethernet. There are similar devices in the storage system for connecting the computer's internal bus and storage network. This type of device that is connected to the storage network on the server is generally referred to as a Host Bus Adaptor HBA. The HBA is the physical connection between the I/O channel inside the server and the I/O channel of the storage system. The most common server internal I/O channels are PCI and Sbus, which are the communication protocols that connect the server CPU to peripherals. The I/O channel of the storage system is actually Fibre Channel. The role of the HBA is to achieve the conversion between the internal channel protocol PCI or Sbus and Fibre Channel protocols.

HBA Principles

The common data communication protocols between servers and storage devices are IDE, SCSI and Fibre Channel. In order to achieve communication between the server and the storage device, both ends of the communication need to implement the same communication protocol. There are usually controllers on the storage device. The controller implements one or several communication protocols, which can convert between storage protocols such as IDE, SCSI or Fibre Channel to operating protocols of physical storage devices. The server communication protocol is implemented by the expansion card or the integrated circuit on the motherboard, which is responsible for the conversion of the server internal bus protocol and storage protocols such as IDE and SCSI. For example, in a PC, the IDE has the function of the IDE protocol on the motherboard, and the IDE disk controller has the function of the IDE protocol. Therefore, the IDE disk can be connected to the IDE cable of the PC. If the disk only supports the SCSI protocol, then the disk cannot be directly connected to the PC. At this time, you need to insert a SCSI card into the expansion slot of the PC. The SCSI disk can be connected to the card. The SCSI card implements a PC bus to SCSI conversion. The function implemented by this SCSI card is the function of the host bus adapter card. If the disk only supports Fibre Channel protocols, then the Fibre Channel protocol needs to be supported on the server, because the high-speed features of Fibre Channel are generally not supported by the server board and require a dedicated host bus adapter card. Once the server is plugged into the host bus adapter card, it can be connected to Fibre Channel-enabled disks via Fibre Channel.

The host bus adapter has a small central processing unit inside it, some of which are used as data buffers and connection devices for connecting Fibre Channel and bus. This small central processor is responsible for the conversion of both PCI and Fibre Channel protocols. It also has other features that initialize the server port connected to the Fibre Channel network, support upper layer protocols such as TCP/IP, SCSI, etc., 8B/10B encoding and decoding.