Apparatus and method for executing controller memory buffer (CMB) based data transfer commands in a distributed data processing environment. In some embodiments, a storage device having a device controller and a main non-volatile memory (NVM) is coupled to a client device via an interface. The client device respectively issues normal data transfer commands and bypass data transfer commands to the storage device. The normal data transfer commands include read and write commands that result in transfer of data between the NVM and the client device using a normal data path through the storage device. The bypass data transfer commands involve an allocated CMB of the storage device directly controlled and accessed by the client device. In this way, write data are directly placed into the CMB for writing to the NVM, and readback data from the NVM are directly recovered from the CMB by the client device.