HP StorageWorks 8/80 HP StorageWorks Fabric OS 6.2 administrator guide (5697-0 - Page 519

XRC emulation The eXtended Remote Copy (XRC) application is a DASD application that implements disk mirroring, as supported by the disk hardware architecture and a host software component called System Data Mover (SDM). The primary volume and the secondary mirrored volume may be geographically distant across an IP WAN. The latency introduced by greater distance creates delays in anticipated responses to certain commands. The FICON pacing mechanism may interpret delays as an indication of a large data transfer that could monopolize a shared resource, and react by throttling the I/O. XRC emulation provides local responses to remote hosts, eliminating distance related delays. A FICON XRC Emulation License is required to enable XRC Emulation. Tape Write Pipelining FICON tape write pipelining improves performance for a variety of applications when writing to tape over extended distances. FICON tape write pipelining locally acknowledges write data records, enabling the host to generate more records while previous records are in transit across the IP WAN. If exception status is received from the device, the writing of data and emulation is terminated. The FICON Tape Emulation License is required to enable FICON Tape Write Pipelining. Tape Read Pipelining FICON tape read pipelining improves performance for certain applications when reading from FICON tape over extended distances. FICON tape read pipelining reads data on the tape directly from the tape device. Reading of tape continues until a threshold is reached. The buffered data is forwarded to the host in response to requests from the host. When the host sends the status accept frame indicating that the data was delivered, the read processing on the device side credits the pipeline and requests more data from the tape. If exception status is received from the device, the reading of data and emulation is terminated. The FICON Tape Emulation License is required to enable FICON Tape Read Pipelining. FICON emulation configuration Before you configure FICON emulation, you will need to understand the available options, and if those options are to be implemented in your installation. If FICON emulation is new to you, please read "FICON emulation concepts and features" on page 514 in this chapter. The syntax for the portcfg ficon command is as follows: portCfg ficon [slot/]ge0|ge1 tunnel_Id config [-x 1|0] [-w 1|0] [-r 1|0] [-t 1|0] [-l 1|0] [-b 1|0] [wrtMaxPipe value] [rdMaxPipe value] [wrtMaxDevs value] [rdMaxDevs value] [wrtTimer value] wrtMaxChains value] [oxidBase value] [dbgFlags value] where: • slot is the number of a slot in a Director chassis that contains a B-Series Multi-protocol Router blade. This parameter does not apply to the stand-alone 400 MP Router. • ge0|ge1 is the Ethernet port used by the tunnel (ge0 or ge1). • tunnel_id is the tunnel number (0 - 7). • config is the option that creates a configuration. • -x 1|0 enables or disables XRC emulation. 1 is enable, O is disable. • -w 1|0 enables or disables tape write pipelining. 1 is enable, O is disable. • -r 1|0 enables or disables tape read pipelining. 1 is enable, O is disable. • -t 1|0 enables or disables TIN/TIR emulation. 1 is enable, O is disable. This option should be enabled when one or all of the following features are enabled: • XRC emulation. • tape write pipelining. • tape read pipelining. • -l 1|0 enables or disables device level ACK emulation. 1 is enable, O is disable. This option should be enabled when one or all of the following features are enabled: • XRC emulation. • tape write pipelining. Fabric OS 6.2 administrator guide 515