To get a first look what Graylog is and how you can work with it we have a virtual appliance that runs on VMWare or Virtualbox. The following will guide you through the first steps of using Graylog.
After you feel comfortable you should create a fresh installation that follows your own requirements regarding the sizing and the security settings. The virtual appliance is only created to have a showcase about the features and is not created to run in production.
If you need assistance in planning or building your logging environment we offer professional support.