Abstract: A host IO devices directly implements host read operations on both local memory, and on peer memory via a PCIe non-transparent bridge. When a host read operation is received by a host IO device from a host, the host IO device uses an API to obtain the physical address of the requested data on the peer memory, and generates a PCIe Transaction Layer Packet (TLP) addressed to the address in the peer memory. The TLP addressed to an address in the peer memory is passed over the NTB to the peer compute node to retrieve the data stored in the addressed slot of peer memory. The requested data is returned to the host IO device over the NTB, stored in a buffer, and read out to the host to directy respond to the host read operation.

Abstract: Mirrored volatile memory in a storage system is configured with a dual cast region of addresses. Buffers in the dual cast region are allocated for data associated with a received Write IO. A host IO device associates the dual cast addresses with the data. A switch or CPU complex recognizes the dual cast addresses associated with the data and, in response, creates and sends a first copy of the data to a first volatile memory mirror and creates and sends a second copy of the data to a second volatile memory mirror. The second copy may be sent via PCIe NTB between switches or CPU complexes.