Patent ID: 7587528

Claim:
A system in communication with a remote host, the system comprising: a primary storage control unit coupled to the remote host; a fibre channel connection coupling the primary storage control unit to the remote host; a processor included in the primary storage control unit; and memory coupled to the processor, wherein the processor performs operations, the operations comprising: receiving, at the primary storage control unit, an information unit from the remote host over a fibre channel connection; and adjusting, by the primary storage control unit, an information unit pacing parameter included in a response sent from the primary storage control unit to the remote host, wherein the information unit pacing parameter indicates the number of information units that the remote host is allowed to send to the primary storage control unit without waiting for any additional response from the primary storage control unit, wherein the information unit is a channel command word in a fibre connect protocol, and wherein the received channel command word starts a channel command word chain, the operations further comprising: (i) determining whether the channel command word comprises a define subsystem operation command that defines a subsystem operation for extended remote copy operations; (ii) determining the number of read record set commands associated with the define subsystem operation command, wherein a read record set command corresponds to a read request, wherein the number of read record set commands indicates the number of read requests that are to follow from the remote host to the primary storage control unit during the extended remote copy operations; and (iii) setting the information unit pacing parameter to a value that is two more than the number of read record set commands to allow the remote host to send remaining information units without requiring the additional response from the primary storage control unit.