David Klee shows one tactic for running out of disk space, in this case on an ESXi host:
Sometimes this task is harder than it sounds. If your SAN is out of space, or the SAN management tools are out of your control, you could be stuck.
But… follow a simple trick to give yourself that last little bit of wiggle room in the event that a snapshot fills a datastore.
Add a large text file to the root of the datastore that you can delete if you need headroom! I know it sounds too simple… but it’s simple and effective.
Filed under “old but good.”