im in process of moving an existing clusters etcd to a local disk, is there a guide anywhere on how to configure rancher to use this and migrate the existing data from where its stored currently, also is it possible to from from a local etcd based setup to a mariadb one on an existing cluster (if not i'll attempt to just continue to use etcd but moving it to another disk)

there is nothing magic about this. Just stop rke2 (run the killall script to ensure that the etcd pod is also stopped), mount the new disk to a temporary path, move the files over, then mount the disk at the old path.

thank you very much sir