By default, flows are saved to the h2oflows directory underneath your home directory. The directory where flows are saved is printed to stdout:

03-20 14:54:20.945 172.16.2.39:54323     95667  main      INFO: Flow dir: '/Users/<UserName>/h2oflows'

To back up saved flows, copy this directory to your preferred backup location.

To specify a different location for saved flows, use the command-line argument -flow_dir when launching H2O:

java -jar h2o.jar -flow_dir /<New>/<Location>/<For>/<Saved>/<Flows>

where /<New>/<Location>/<For>/<Saved>/<Flows> represents the specified location. If the directory does not exist, it will be created the first time you save a flow.