You can also set whether CrushFTP is using XML files for its users and groups, or if its using SQL for this.  We do not recommend using SQL for the backend storage of users.  While it is supported, it adds another potential point of failure, adds delays for the login process as SQL is queried for results, and has limitations on column sizes for large data structures like "events" or "custom css" and "custom javascript" and others.  It's only suggested to use this method when forced to use it by company policy that ignores our recommendation of best practice.  CrushFTP supports replication and clustering of user configuration across multiple locations using the normal XML database of users.