Systems and methods for avoiding host level busy and retry latencies

A method, comprising:

• receiving a command from a first system;
• determining which resources are required to process the command;
• checking for the required resources before receiving unsolicited data associated with the command;
• receiving the unsolicited data from the first system;
• checking for the required resources after receiving the unsolicited data when the checking for the required resources before receiving the unsolicited data indicated that the required resources were not available before receiving the unsolicited data;
• sending a status to the first system if the required resources are not available after receiving the unsolicited data;
• and
• processing the command if the required resources are available either before receiving the unsolicited data or after receiving the unsolicited data.

A computer program product for processing a command, the computer program product comprising:

• a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code configured to receive a command from a first system;
• computer readable program code configured to determine which resources are required to process the command after receipt thereof;
• computer readable program code configured to check for the required resources before receiving data associated with the command;
• computer readable program code configured to receive the data from the first system;
• computer readable program code configured to check for the required resources after receiving the data when the checking for the required resources before receiving data indicated that the required resources were not available before receiving the data;
• computer readable program code configured to send a status to the first system if the required resources are not available after receiving the data;
• computer readable program code configured to at least begin to process the command if the required resources are available before receiving the data;
• and
• computer readable program code configured to fully process the command when the required resources are available.

A system, comprising:

• logic adapted for receiving a command from a first system, the command adhering to a fibre channel protocol which provides for unsolicited data to be sent shortly after the command;
• logic adapted for determining which resources are required to process the command;
• logic adapted for checking for the required resources before receiving data associated with the command;
• logic adapted for receiving the data from the first system;
• logic adapted for receiving a sequence initiative from the first system;
• logic adapted for checking for the required resources after receiving the data when the checking for the required resources before receiving data indicated that the required resources were not available before receiving the data;
• logic adapted for sending a status to the first system if the required resources are not available after receiving the data;
• and
• logic adapted for processing the command if the required resources are available either before receiving the data or after receiving the data,
• wherein at least one of the first system and the second system comprise a direct access storage device.