Host bus adapters (HBAs) are a card and/or IC adapter that has input/output (I/O) process and physical property between servers and storage devices. As a result of HBAs scale back the burden on the host processor in knowledge storage and retrieval tasks, it will improve server performance. A hba card and a disk system that’s connected to that are typically known as a disk channel.
The overall definition of HBAs:
- I/O adapters that connect the host I/O bus and therefore the hardware system. Consistent with this definition, just like the video card is connected to the pc and memory. The NIC is connected to the network bus and memory, the small computer system interface-FC card is connected to the SCSI or FC bus and memory, they ought to be thought of as HBAs. HBA cards embody FC-HBA and iSCSI HBAs and alternative HBA cards within the future, however HBAs are usually employed in SCSI. Adapters (adapters) and NICs are used for FC, and NICs are used for LAN and Token Ring networks.
- We all know that a computer is generally connected by 2 buses, a bus known as the system bus, associate degree other called an I/O bus. System bus on the CPU, memory, cache so on, I/O bus is the peripheral equipment, and currently the foremost common is the PCI bus.
- The system bus is just like the main road within the district and the I/O bus is just like the highway within the business space. System bus and I/O bus information measure units are Gbyte to remember. However, it’s obvious that the most highway and commercial area of the district compared to the backbone. The previous is actually a lot of “core”, wider, smoother, style needs are high.
- Though the I / O bus speed is far not up to the system bus bandwidth. Regardless of the outcome is Gbyte to measure, and that we apprehend the speed of peripheral devices. It is easy, we have a tendency to be about to organize the peripherals, connected to the I / O bus! HBA refers to the Host and that I/O BUS directly associates degree adapter.
The importance of HBAs:
- Within the early SAN storage system, the server and therefore the switch knowledge transmission is thru the fiber, as a result of the server. The small computer system interface instruction to the storage device, can’t take the normal computer network network informatics protocol. Therefore the ought to use FC transmission. Thus this SAN is named FC-SAN, and later appeared within the IP protocol package SAN. Will take the normal computer network network, so called IP-SAN. The foremost typical of that is currently the popular ISCSI.
- These 2 strategies need to do an important knowledge packet unpacking package operation. So a superior SAN system needs a network card that’s dedicated to unpacking the server to scale back the burden on the processor. This NIC is called the HBA card, which additionally to the work of the unpack, of course. It can also provide a fiber interface for the corresponding switch connection.
- HBA physically you’ll be able to plug it into a PCI or PCI slot as a network card, therefore the use of this device is far sort of a network card. Lots of folks confuse it with a common NIC or a common fiber-optic card. Of course, some iSCSI HBA cards are often used as a traditional network card. However, it’s terribly uneconomical to think about the price.
The principle of the HBA:
- The common electronic communication protocol between servers associated with degreed storage devices is the IDE, SCSI, and Fibre Channel. A controller is usually obtainable on a storage device. The communication protocol of the server is enforced by an computer circuit of the enlargement card or motherboard. That is to blame for the conversion of the server bus protocol. Therefore the IDE associate degreed small computer system interface storage protocols.
- If the disk solely supports SCSI protocols, the disks can not be directly connected to the PC. You would like to insert a SCSI card on the PC slot and the SCSI disk can be connected to the card. SCSI card allows PC bus to SCSI conversion. This type of SCSI card performs the host Bus adapter card function. If the disk supports solely Fibre Channel protocols. Then the Fibre Channel protocol is needed on the server as a result of the high-speed characteristics of the Fibre Channel.
- Host bus adapter card incorporates a tiny CPU, some memory as an information cache and connects the fiber channel and bus association devices. This small CPU is to blame for the conversion of PCI and Fiber Channel protocols. It conjointly has other functions to initialize the server port connected to the Fiber Channel network. Support higher layer protocols similar to protocol / IP, SCSI, 8B / 10B cryptography and decoding.
Relationship between Fiber Optic Network Interface Card (NICs) and HBAs:
Owing to the various transmission protocols, the network cards are often divided into 3 kinds, one is LAN card. The opposite is Fiber Channel network card, and three is the iSCSI network card.
LAN Network Card:
The name of the LAN Adapter, the transmission protocol is associate degree informatics protocol. It is usually connected to an LAN switch through a fiber optic cable or twisted pair. The interface sorts are divided into optical and electrical ports. Optical ports are generally transmitted through fiber optic cables, the interface module is usually SFP (transmission rate GB) and GBIC (1GB/s). The corresponding interface is SC, ST and LC. This usually used interface sort is RJ45, it’s wont to connect with twisted pairs, conjointly has an interface with homocentric cable. However, currently it is used less.
FC Network card:
Usually also known as fiber optic network card, scientific name Fibre Channel HBA. The transport protocol may be a Fiber Channel protocol and is usually connected to a Fiber Channel switch through a fiber optic cable. The interface sort is split into optical port and electrical port. The optical interface is usually through the fiber optic cable for knowledge transmission. The interface module is generally SFP and GBIC (1Gb / s), the corresponding interface for the SC and LC. The interface form of the electrical interface is generally a DB9 pin or HSSDC.
iSCSI Network card:
The name of the iSCSI HBA, the Transport iSCSI protocol and therefore the interface sort is the same because of the LAN card.
We are saying “fiber-optic network card” generally refers to the FC HBA card, infix the server, storage device with the fiber switch. Optical LAN card is usually known as “fiber LAN card” is additionally inserted within the server. However, it external is that the LAN switch with the optical port.