Docker Create Volume With Mountpoint

i want to create a volume in docker/portainer for my raspberri pi’s.

i have set up a NFS server on one of the pi’s and connected the other pi so that it can read/write to the NFS. (this is working as expected).

i now want to make a named docker volume so that i can use volume in portainer.

looking at the documentation, i have created the following command:

sudo docker volume create --driver local \
    --opt type=nfs \
    --opt device=:/mnt/nfs/volumes/minio-config \

but when i look at the volume in portainer, it shows the mount point being set to: /var/lib/docker/volumes/minio-config/_data

i have tried creating the volume from within portainer and i still get the same result.