A HostBusAdapter(HBA) is a hardware component in storage networks through which servers connected to a network transfer their data to other components. It is an adapter card for a server, a host or a disk controller, which is plugged into the corresponding bus in the computer.
The function of the HBA adapter is similar to that of a network interface card( NIC) with the difference that the term Host Bus Adapter (HBA) is used for components connected to SCSI, Fibre Channel( FC), eSATA, SATA or in the case of RDMA over Converged Ethernet( RoCE). On the other hand, storage components that are connected to Integrated Drive Electronics( IDE), Ethernet, FireWire or the USB interface are also called host bus adapters. HBA adapters have very low latencies, which are around 10 µs to 20 µs and which add to the storage latency. HBA adapters increase the efficiency of data storage and readout.