US 9,195,626 B2 · Reducing write I/O latency using asynchronous Fibre Channel exchange

Abstract

A FCP initiator sends a FCP write command to a FCP target within a second FC Exchange, and the target sends one or more FC write control IUs to the initiator within a first FC Exchange to request a transfer of data associated with the write command. The first and second FC exchanges are distinct from one another. A payload of each write control IU includes an OX_ID value with which the initiator originated the second Exchange and a RX_ID value assigned by the FCP target for the second exchange. The two Exchanges yield a full-duplex communication environment between the initiator and target that enables the reduction or elimination of latencies incurred in a conventional FCP write I/O operation due to the half-duplex nature of a single FC Exchange. The write control IU may be an enhanced FCP_XFER_RDY IU or a new FC IU previously undefined by the FCP standard.

Claims20

Dependent claims

A Fibre Channel (FC) Protocol for SCSI (FCP) target, comprising:

a FC port;
and
a processor, adapted to communicate with a FCP initiator via the FC port;
wherein the FCP target is configured to send one or more FC write control information units (IUs) to the FCP initiator within a first FC exchange to request a transfer of data associated with a FCP write command IU previously sent to the FCP target by the FCP initiator within a second FC exchange, without the FCP initiator first sending its sequence initiative in the second FC exchange;
wherein the first FC exchange is distinct from the second FC exchange;
wherein a payload of each of the one or more write control IUs comprises:
an originator exchange identifier (OX_ID) value with which the FCP initiator originated the second FC exchange;
and
a responder exchange identifier (RX_ID) value assigned by the FCP target for the second FC exchange.

6 more elements

A Fibre Channel (FC) Protocol for SCSI (FCP) initiator, comprising:

a FC port;
and
a processor, adapted to communicate with a FCP target via the FC port;
wherein the FCP initiator is configured to receive one or more FC write control information units (IUs) from the FCP target within a first FC exchange requesting a transfer of data associated with a FCP write command IU previously sent to the FCP target by the FCP initiator within a second FC exchange, without the FCP initiator first sending its sequence initiative in the second FC exchange;
wherein the first FC exchange is distinct from the second FC exchange;
wherein a payload of each of the one or more write control IUs comprises:
an originator exchange identifier (OX_ID) value with which the FCP initiator originated the second FC exchange;
and
a responder exchange identifier (RX_ID) value assigned by the FCP target for the second FC exchange.

6 more elements

Dependencies are inferred from the claim text.

Reducing write I/O latency using asynchronous Fibre Channel exchange

Life of this patent

Reducing write I/O latency using asynchronous Fibre Channel exchange

Life of this patent

Abstract

Claims20