Storage control apparatus and method for controlling number of commands executed in storage control apparatus

摘要

A storage control apparatus of the present invention controls the number of multiple commands issued from a host machine without shutting down the host machine. A communication port of the storage control apparatus carries out communications with the hosts in accordance with the iSCSI protocol. Command processing resources are managed for each communication port. A resource allocation control part calculates the number of commands capable of being received on the basis of the remaining amount of command processing resources inside shared port resources, a change in the number of commands received from a host, communication delay time, and the state of execution of a command issued from a host or the like. A MaxCmdSN is calculated by adding the results of command processing by a command execution part and the receivable number calculated by the resource allocation control part to the value of the latest CmdSN received from a host. The storage control apparatus adds the MaxCmdSN to a transmission frame and transmits it to the host.