In an NVMe-based storage system, a host is connected to an NVMe controller through a PCIe bus, and the NVMe controller is connected to a storage medium. The NVMe controller receives from the host a data packet that carries payload data and an association identifier. The association identifier associates the payload data with a write instruction. The NVMe controller obtains the write instruction according to the association identifier, and then writes the payload data into the storage medium according to the write instruction.