The Simple Guide to Host Bus Adapter(HBA)
A host bus adapter (HBA) is a integrated circuit adapter which provides physical connectivity between server and storage devices. It is responsible for input/output support and processing. A host bus adapter can also be called host controller or host adapter. Most of time, a HBA works as an expansion card that plugs into the bus of a server’s motherboard. The main purpose of HBA is to realize the data transmission of internal channel protocol between PCIe and SAS or Fibre Channel. HBA integrated with SAS port is called SAS HBA, while HBA integrated with optic port is called Fibre Channel HBA. Sometimes, the devices for connecting to IDE, Ethernet, Fire Wire, USB and other systems may also be called host adapters.
SAS is the abbreviation of Serial Attached SCSI, which is a point-to-point serial protocol that moves data to and from computer-storage devices such as hard drives and tape drives. It replaces the older Parallel SCSI . SAS offers optional compatibility with Serial ATA (SATA). So a SAS HBA can support a SAS device as well as a SATA device.
A common SAS HBA is made up by a slight circuit board embedded controller chips, one or more SAS/SATA ports,a x4 or x8 PCIe interface and a profile bracket. The bus interface is on the side of circuit board, which is inserted into the server motherboard. The SAS or SATA interface is integrated on the other side of the circuit board. Sometimes, a heat sink may be installed on it. Generally, SAS HBA can be classified as Internal card and External card.
Let me show you an example. Above picture is a 10Gtek6Gb/s Internal PCI Express to SAS/SATA HBA Card, which is compatible for LSI 9211-8I. You can see a PCIe connector on the side of circuit board, which is X8 lane. The interface’s standard is PCIe 2.0, which means it can support up to 6Gb/s. On the right side of the circuit board, you can see 2 internal mini SAS SFF-8087 ports, which need mini SAS cables to connect with one or two storage devices. The SAS standard has the data rate of 3,6,12 and 24Gb/s.The latest SAS standard completed in 2017, which is called SAS 4th generation supporting speed up to 24Gb/s.
Fibre Channel HBA
Besides SAS HBA, Fibre Channel HBA is also commonly used in some application, especially in commercial data center. Fibre Channel is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data, primarily used to connect computer data storage to servers. It has progressed at the data rate of 1, 2, 4, 8, 16, 32, and 128Gb/s. Fibre Channel typically runs on optic fibers within and between data centers, so Fibre Channel HBAs need to connect with transceivers and optic fibers to work. The main structure of Fibre Channel HBA looks like SAS HBA, but it has optic ports rather than SAS ports. The form of Fibre Channel HBA varies from vendor to vendor. Some products can connect with optic fibers directly, while some products need optic modules, such as SFP(1.25G) or SFP+(10G).
Below figure is an example product from QLogic. It is integrated PCIe 3.0 x8 connector,which can support speed up to 16Gb/s. It has two options of SFP+ ports, single-port or dual-port. Both are include LC connector.
Both SAS HBA and FC HBA can connect a host server to a storage device or a switch, serving as the connecting point in the SAN management system. Fibre Channel HBA is more popular in commercial data center because of higher speed and more effective performance. FC HBA can also connect multiple storage systems, or connect multiple servers when servers are used as both application hosts and storage systems.
Broadcom, Promise Technologies, Adaptec, HP, QLogic, Areca, LSI and ATTO Technology are major vendors who sells SAS HBA cards, while the major vendors of FC HBA cards are QLogic, Emulex and Broadcom. Other manufacturers of FC HBA cards include Agilent, ATTO, and Brocade. 10Gtek provide two kinds of SAS/SATA HBA cards with unleashed performance, operational agility and maximum power of cloud virtualization. Please find more details in:
6Gb/s Internal PCI Express SAS/SATA HBA RAID Controller Card, compatible for LSI 9211-8I
6Gb/s External PCI Express SAS/SATA HBA, compatible for LSI 9200-8E