My cluster will not come up. The datadir is full. Can I just copy the data to a new bigger directory then start the cluster? And edit the config file to reflect the changes?
Yes that should work. Make sure you move the entire current data directory to the new location. Verify all your permission match the old data directory. Once you have the prep work complete update the my.cnf with the new data directory location and then start mysql.
Don’t forget to bootstrap the first node after you move the datadir.