I have a Debian instance having a root EBS volume of 500 GB. I want to reduce the size to 80 gb as that much storage is not required. AWS doesn't allow me to reduce the current EBS volume so I tried creating another one with dev/xvdf and attached it to the instance now what's next should I do so that I can mount dev/xvdf as dev/xvda (root) without affecting the current data stored in the root volume?
AFAIK this is not straightforward. You would have to create a new volume of 80GB, copy all the data from the old volume to the new one, and boot a new instance using the new volume.