I just noticed the nanopi r5c images were updated. In particular, I tested the OMV6 image on my r5c. It works everything as I expected. The transfer speed can reach over 250MB/s. However, I found a strange behavior. When I created a new username. It could not be used to login through ssh. What I found was that it was not contained in the ssh group. By doing an "sudo usermod -aG ssh <username>" solved this problem. In addition, an "sudo usermod -aG sudo <username>" is also necessary. I copy this can be added during next update.
Another strange thing I found was that if I use the new debian core image to build my own OMV6, the transfer speed was very slow, only over 10MB/s. I am wondering what I did wrong. I hope somebody can enlightening me on this.
Overall, very good work. Thank you very much.