Internet small computer interface systems extension for remote direct memory access (RDMA) for distributed hyper-converged storage systems

A target apparatus, comprising:

• a non-transitory memory comprising executable instructions;
• and
• a processor in data communication with the non-transitory memory and configured to execute the executable instructions to cause the target apparatus to perform operations comprising:
• receiving an incoming packet from an initiator apparatus, the incoming packet encapsulated by the initiator apparatus using an Internet Small Computer Systems Interface (iSCSI) extension for remote direct memory access (RDMA) (iSER) of the initiator apparatus;
• decapsulating the incoming packet to access a Small Computer Systems Interface (SCSI) read command indicating an input/output (I/O) operation to perform at a distributed storage system;
• allocating a scatter-gather list in a memory of the target apparatus for storing data received from the distributed storage system as a result of performance of the I/O operation;
• storing the data in the scatter-gather list;
• encapsulating the data in the scatter-gather list to generate a SCSI DATA-IN PDU including the data, wherein the SCSI DATA-IN PDU is stored in the scatter-gather list;
• encapsulating the SCSI DATA-IN PDU to generate an outgoing iSCSI protocol data unit (PDU) including the SCSI DATA-IN PDU, wherein the outgoing iSCSI PDU is stored in the scatter-gather list;
• assigning ownership of the scatter-gather list storing the iSCSI PDU to an iSER of the target apparatus;
• encapsulating the iSCSI PDU to generate an outgoing iSER packet;
• and
• transmitting the outgoing iSER packet to the initiator apparatus.

A non-transitory computer readable medium having instructions stored thereon that, when executed by a target device, cause the target device to perform operations comprising:

• receiving an incoming packet from an initiator device, the incoming packet encapsulated by the initiator device using an Internet Small Computer Systems Interface (i SC SI) extension for remote direct memory access (RDMA) (iSER) of the initiator device;
• decapsulating the incoming packet to access a Small Computer Systems Interface (SCSI) read command indicating an input/output (I/O) operation to perform at a distributed storage system;
• allocating a scatter-gather list in a memory of the target device for storing data received from the distributed storage system as a result of performance of the I/O operation;
• storing the data in the scatter-gather list;
• encapsulating the data in the scatter-gather list to generate a SCSI DATA-IN PDU including the data, wherein the SCSI DATA-IN PDU is stored in the scatter-gather list;
• encapsulating the SCSI DATA-IN PDU to generate an outgoing iSCSI protocol data unit (PDU) including the SCSI DATA-IN PDU, wherein the outgoing iSCSI PDU is stored in the scatter-gather list;
• assigning ownership of the scatter-gather list storing the iSCSI PDU to an iSER of the target device;
• encapsulating the iSCSI PDU to generate an outgoing iSER packet;
• and
• transmitting the outgoing iSER packet to the initiator device.

A method of processing an incoming packet by a target device associated with a distributed storage system, the method comprising:

• receiving the incoming packet from an initiator device, the incoming packet encapsulated by the initiator device using an Internet Small Computer Systems Interface (iSCSI) extension for remote direct memory access (RDMA) (iSER) of the initiator device;
• identifying a remote I/O buffer offset in an iSER header of the incoming packet, the remote I/O buffer offset being associated with a remote I/O buffer at the initiator device, the remote I/O buffer including data associated with a SCSI write command in the incoming packet;
• storing the remote I/O buffer in a memory of the target device;
• decapsulating, at an iSER of the target device, the incoming packet to access an Internet Small Computer Systems Interface (iSCSI) packet data unit (PDU);
• decapsulating the iSCSI PDU to access the SCSI write command;
• allocating a scatter-gather list in the memory for storing the data associated with the SCSI write command;
• performing an RDMA operation to read the data from the remote I/O buffer of the initiator device;
• storing the data into the scatter-gather list;
• and
• causing a write operation associated with the SCSI write command to be performed by the distributed storage system, wherein the distributed storage system accesses the scatter-gather list to perform the write operation using the data in the scatter-gather list.