Benefits of Host Bus Adaptar: 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: 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: Benefits of HBA data buffer Need for data buffering. Credit of buffer. Calculate the credit requirement. Fibre channel architecture. Hardware context cache. Performance benefits. Need for data buffering: 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: 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:
Calculate the credit requirement We can calculate the credit easily. Light travelling 5 ns so the round trip latency of data 10 km
cable in 100 milliseconds. Multiple frame must be fully utilized the link benefit. When it operating 2 Gbps instead of 1 Gbps then twice the buffer credit needed to fully utilized the bandwidth.
Fibre channel architecture: 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 : 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: 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 : 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 : Contact Details 188-M Technology Drive Irvine CA 92618 Tel: (949) 788-9939 Fax: (949) 788-9940 www.shopricom.com