Abstract: A method for managing storage space in a storage port queue includes establishing a watermark for the storage port queue. The method further receives, at the storage port associated with the storage port queue, a command having an initiator-target-LUN (ITL) nexus associated therewith. Upon receiving the command, the method determines whether the used space in the storage port queue has reached the watermark. In the event the used space has not reached the watermark, the method processes the command. In the event the used space has reached the watermark and a specified number of commands for the ITL nexus are already present in the storage port queue, the method rejects the command. Otherwise, the method may process the command. A corresponding apparatus and computer program product are also disclosed herein.

Abstract: A method for verifying the integrity of a communication link is disclosed herein. In selected embodiments, such a method may include detecting, during normal operation of a communication link, a condition indicative of a high failure rate (HFR) on the communication link. The method may further include placing the communication link in an HFR state as a result of the condition. While in HFR state, the method may repeatedly transmit test I/Os over the communication link. The method may then automatically exit HFR state and resume normal operation on the communication link when one or more of the following has occurred: a selected number of test I/Os have been successfully transmitted over the communication link, and a number of test I/Os have been successfully transmitted over the communication link for a selected period of time. A corresponding system, apparatus, and computer program product are also disclosed and claimed herein.

Abstract: A method for logging a repetitive error in a computer system is provided. The repetitive error is logged after each of a series of progressively increasing time periods. The logging commences when the repetitive error is first identified and concludes when the repetitive error is no longer identified.

Abstract: A method for initializing a fiber channel link upon a failure of a standard speed negotiation algorithm is provided. The standard speed negotiation algorithm is disabled. A link speed is set to a highest possible link speed not yet attempted outside the standard speed negotiation algorithm, initializing the fiber channel link if the link speed is negotiated at a maximum link speed. If the link speed is negotiated at a speed less than the maximum link speed, the standard speed negotiation algorithm is reattempted, initializing the fiber channel link according to the standard speed negotiation algorithm if the reattempt is successful.

Abstract: A method, system, and computer program product to preserve data integrity in a mirror and copy environment is disclosed herein. In one embodiment, a method may include receiving a write command and data from a host device. The method may further include writing the data to a primary storage device and attaching a primary sequence number associated with the primary storage device to the write command, thereby providing a numbered write command with a command sequence number. The numbered write command may then be transmitted to a secondary storage device. The method may further include comparing the command sequence number to a secondary sequence number associated with the secondary storage device. If the command sequence number matches the secondary sequence number, then the command may be executed. Otherwise, it may be ignored.

Abstract: A method for initializing a fibre channel link upon a failure of a standard speed negotiation algorithm is provided. The standard speed negotiation algorithm is disabled. A link speed is set to a highest possible link speed not yet attempted outside the standard speed negotiation algorithm, initializing the fibre channel link if the link speed is negotiated at a maximum link speed. If the link speed is negotiated at a speed less than the maximum link speed, the standard speed negotiation algorithm is reattempted, initializing the fibre channel link according to the standard speed negotiation algorithm if the reattempt is successful.

Abstract: A method for logging a repetitive error in a computer system is provided. The repetitive error is logged after each of a series of progressively increasing time periods. The logging commences when the repetitive error is first identified and concludes when the repetitive error is no longer identified.

Abstract: A log-in resource release system includes a set of lists for managing log-in requests to a processing cluster input/output port from host server input/output ports. Host servers that have been granted memory structures within a memory storage device (“configured hosts”) are granted priority access to a storage processing device's input/output port (“cluster port”). If the cluster port has exhausted its log-in resources, log-on requests from non-configured hosts will be not be accepted. New log-in requests from configured hosts will cause a host connected at a link or transport layer but not an upper layer to be logged off. If no hosts are connected only at the link or transport layer, a non-configured host connected at an upper layer will be logged off. If only configured hosts are connected and only at the upper layer, the log-on request by the configured host will be denied.