Method and apparatus for asynchronous discovery of processing and storage nodes coupled via an expander switch in a fabric. In some embodiments, an initiator device operates as a processing node to transfer data to and from a non-volatile memory (NVM) of a target device at a storage node. One of the initiator or target devices is activated prior to the other device. The second activated device broadcasts a discovery command responsive to the activation of the second activated device and prior to receipt of a request for the discovery command from the first activated device. The first activated device processes the discovery command to establish an I/O communication link between the first activated device and the second activated device. The discovery command may include a non-volatile memory express (NVMe) controller list, and the NVM may be arranged as one or more NVMe namespaces.