Rpi 3 SD card for the system files and a USB DRIVE as the storage device

How do we do this with LE ?

Thanks

Ok thanks wasn't sure

So curious would this command line be better
boot=UUID=C446-C2C7 disk=UUID=3aeade4e-9b9a-4ec8-ab2d-08f6075e06f2 quiet

than the old
boot=/dev/mmcblk0p1 disk=/dev/sda1 ssh quiet

Bump ...so is UUID better ?...more stable ??

Thanks