Method to prevent I/O starvation of slower hosts in a multi-host environment

A system comprising:

• a processor;
• a data bus coupled to the processor;
• and
• a computer-usable medium embodying computer program code, the computer-usable medium being coupled to the data bus, the computer program code used for managing control unit input/output (I/O) operations in a multi-host environment and comprising instructions executable by the processor and configured for:
• generating a set of busy status messages in response to receiving a corresponding set of I/O requests generated by an associated set of hosts, the set of busy status messages generated by a storage control unit when it has insufficient resources to process the set of I/O requests, each of the set of busy status messages comprising a CUBusy message, the CUBusy message being defined by a Fibre Connection protocol;
• generating a set of availability status messages when the utilization of the storage control unit's resources subsides to a first utilization value, the first utilization value representing a percentage of resources of the storage control unit, the set of availability status messages corresponding to the set of busy status messages, each of the set of availability status messages comprising a CUEnd message, the CUEnd message being defined by the Fibre Connection protocol;
• providing a first subset of the set of availability status messages to a first subset of the set of hosts;
• and
• providing a second subset of the set of availability status messages to a second subset of the set of hosts, the provision of the second subset of the set of availability status messages delayed until a predetermined time interval has elapsed.

A non-transitory, computer-readable storage medium embodying computer program code, the computer program code comprising computer executable instructions configured for:

• generating a set of busy status messages in response to receiving a corresponding set of I/O requests generated by an associated set of hosts, the set of busy status messages generated by a storage control unit when it has insufficient resources to process the set of I/O requests, each of the set of busy status messages comprising a CUBusy message, the CUBusy message being defined by a Fibre Connection protocol;
• generating a set of availability status messages when the utilization of the storage control unit's resources subsides to a first utilization value, the first utilization value representing a percentage of resources of the storage control unit, the set of availability status messages corresponding to the set of busy status messages, each of the set of availability status messages comprising a CUEnd message, the CUEnd message being defined by the Fibre Connection protocol;
• providing a first subset of the set of availability status messages to a first subset of the set of hosts;
• and
• providing a second subset of the set of availability status messages to a second subset of the set of hosts, the provision of the second subset of the set of availability status messages delayed until a predetermined time interval has elapsed.