# list all fisks
lsblk -f

# unmount forced
# you can try the lazy unmount option, which will immediately remove the filesystem from the file hierarchy and postpone the cleanup:
umount --lazy /mnt

# make partition
fdisk /dev/sdX
fdisk p # existing partitions
# Press n to create a new partition.
# press w to write the changes to the disk.
sudo mkfs.ext4 /dev/sdXN
# mount 

docker run -d -p 8000:8000 -p 9000:9000 --name=portainer --restart=always --pull=always -v /var/run/docker.sock:/var/run/docker.sock -v /mnt/apps/docker_volumes/portainer_data:/data portainer/portainer-ce