Recently I found myself migrating, again, my cloud hosting provider. I like to keep a complete backup of all files so that in case I miss something it’s not forever lost in the ether.
This command comes in handy to rsync everything from one host to a backup location, which I can then use to migrate to the new cloud provider. This command skips the docker device mapper along with the other non-FS files in /dev /proc and /sys. Worked for me!
rsync -av --numeric-ids --exclude='/dev' --exclude='/proc' --exclude='/sys' --exclude='/var/lib/docker/devicemapper/' --progress --inplace --rsh='ssh -p22221' / firstname.lastname@example.org:/backups/backupdirectory