HP StorageWorks 8/80 HP StorageWorks Fabric OS 6.2 administrator guide (5697-0 - Page 471

Constraints for FCIP Fastwrite and Tape Pipelining Consider the constraints described in Table 95 when configuring tunnels to use either of these features. Table 95 Using FCIP Fastwrite and Tape Pipelining FCIP Fastwrite Tape pipelining Each GbE port supports up to 2048 simultaneous accelerated exchanges, which means a total of 2048 simultaneous exchanges combined for Fastwrite and Tape Pipelining. Each GbE port supports up to 2048 simultaneous accelerated exchanges, which means a total of 2048 simultaneous exchanges combined for Fastwrite and Tape Pipelining. Does not affect FICON traffic Does not affect FICON traffic FCIP Fastwrite and FC Fastwrite are mutually exclusive. Tape pipelining uses FCIP Fastwrite, not FC Fastwrite. Does not support multiple equal-cost path configurations (see "FCIP Fastwrite and Tape Pipelining configurations"). Does not support multiple equal-cost path configurations or multiple non-equal-cost path configurations (see "FCIP Fastwrite and Tape Pipelining configurations"). Class 3 traffic is accelerated with Fastwrite. Class 3 traffic is accelerated between host and sequential device. With sequential devices (tape drives), there are 1024 initiator-tape (IT) pairs per GbE port, but 2048 initiator-tape-LUN (ITL) pairs per GbE port. The ITL pairs are shared among the IT pairs. For example: Two ITL pairs for each IT pair as long as the target has two LUNs. If a target has 32 LUNs, 32 ITL pairs for IT pairs. In this case, only 64 IT pairs are associated with ITL pairs. The rest of the IT pairs are not associated to any ITL pairs, so no Tape Pipelining is performed for those pairs. By default, only Fastwrite-based acceleration is performed on the unassociated pairs. Does not support multiple non-equal-cost path between host and sequential device FCIP Fastwrite and Tape Pipelining configurations To help understand the supported configurations, consider the configurations shown in the two figures below. In both cases, there are no multiple equal-cost paths. In Figure 79, there is a single tunnel with Fastwrite and Tape Pipelining enabled. In Figure 80, there are multiple tunnels, but none of them create a multiple equal-cost path. Connection can be VE-VE or VEX-VE Figure 79 Single tunnel, Fastwrite and Tape Pipelining enabled Fabric OS 6.2 administrator guide 467