By default, Artifactory puts the Derby DB under $ARTIFACTORY_HOME/data folder.
If you want to put that folder on a network location, you can simply create a symlink to the entire data folder (with the filestore) to a different location.
Please note that putting the DB on a network location may cause problems. You may consider changing the database to one of the other supported DBs (MySQL, Oracle, PostgreSQL, MSSQL).
You can find more information here.