METHODS AND STRUCTURE FOR BUFFERING HOST REQUESTS IN SERIAL ATTACHED SCSI EXPANDERS

摘要

Methods and structure are provided for “spoofing” an active connection between a Serial Attached SCSI (SAS) initiator and a SAS target. The structure includes a SAS expander, comprising multiple physical links with associated transceivers (PHYs), switching hardware, a memory, and a control unit. Each PHY is operable to receive incoming Open Address Frames (OAFs) from SAS initiators that request connections with target devices. The switching hardware is operable to selectively link PHYs of the expander with each other to enable connections between initiators and target devices. The control unit is operable to determine that a connection requested by a received OAF cannot be completed, is operable to transmit an OPEN ACCEPT to the SAS initiator that transmitted the OAF responsive to making the determination, and is operable to store I/O received from the SAS initiator for the requested connection in the memory, responsive to transmitting the OPEN ACCEPT.

主权项

1. A Serial Attached SCSI (SAS) expander, comprising:
multiple physical links with associated transceivers (PHYs), wherein each PHY is operable to receive incoming Open Address Frames (OAFs) from SAS initiators that request connections with target devices; switching hardware operable to selectively link the PHYs of the expander with each other to enable connections between initiators and target devices; a memory; and a control unit operable to determine that a connection requested by a received OAF cannot be completed, operable to transmit an OPEN ACCEPT to the SAS initiator that transmitted the OAF responsive to making the determination, and operable to store incoming I/O received from the SAS initiator for the requested connection in the memory, responsive to transmitting the OPEN ACCEPT.