Backup policy

Hi Team,

We are upgrading RHEL7 to 8 and installed ES. We have NAS mount in place and restored all indices. So in the process of cutover from rhel 7 to 8, we have to add the backup policy to rhel 8 for snapshot. we have total of 4tb mount space and consumed 3.1tb. do we need to delete rhel7 snaps first to get some space?