Ubuntu add a swap file into another disk

$sudo fallocate -l 16G /SWAPDISK/swapfile

$ sudo chmod 600 /SWAPDISK/swapfile

$ sudo mkswap /SWAPDISK/swapfile
Setting up swapspace version 1, size = 16 GiB (17179865088 bytes)
no label, UUID=20859f1c-acc8-43e4-806f-c8f6339b1601

$ sudo swapon /SWAPDISK/swapfile

sudo nano /etc/fstab

sudo swapon --show