Benefits of Host

Bus Adaptar

Buffer is a memory storage to

temporarily hold data. To

transfer data from different

devices this memory portion is

used

What is host bus

adapter

Host bus adapter is a circuit

board or integrated circuit

adapter it provides I/O

processing between physically

connected devices. It uses a microprocessor for storage and

retrieving of data. It has

associated disk subsystem it

sometimes called disk channel.

Benefits of HBA

data buffer

1) Need for data buffering.

2) Credit of buffer.

3) Calculate the credit

requirement.

4) Fibre channel architecture. 5) Hardware context cache.

6) Performance benefits.

Need for data

buffering

Application like remote

backup wide campus SAN

movement of high

bandwidth data over

extended distance. Key enabler to improve the

high distance is the buffer

of HBA. System with

heavy loaded PCI bus also

benefitted from buffer HBA.

Credit Buffer

In the Fibre channel data

is organized in a frame.

Size depends on 512 bytes

to 2 KB. Using buffer

credit mechanism it can transfer maximum amount

of data. It deliver

significantly high

performance in the lower

CPU overhead.

Calculate the

credit

requirement

Fibre channel

architecture

HBA with large data buffer

maintains high throughput

over long distance. Other

performance is impacted

due to it’s limited number of frames buffers. In long

distance like 10 km it

provides more than twice

performance than HBA

without large buffer.

Hardware

context cache

When HBA initiates I/O

command it stores

information to uniquely

identifying command. This

information is called context information it

must be correctly match

to the I/O command. When

data returned from I/O

command to the HBA it must also be matched

with context info.

Performance

Benefit

HBA dramaticaly limit the

performance in the

switched febric SAN.

Under the I/O febric load it

maintains the high throughput. In the switch

febric environment it’s

hardware context switch

provides more than twice

performance.

Advantage of

Host Bus

Adaptar HBA provides

performance advantage

using the feature of

hardware context and

large data buffer. In the higher bandwidth

performance hardware

context cache maintains

high performance. It has

the ability to increase link data rate. Example of this

type of bus is Sun SG-

XPCIE2FC-QF4 PCI

Express Host Bus

Adapters

Contact Details

188-M Technology Drive

Irvine CA 92618

Tel: (949) 788-9939

Fax: (949) 788-9940

www.shopricom.com

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