What is in the SampleDB and can I delete it? I'm not so sure it's useful and it's eating up 10G of disk space.
Huh, 10 gig? I guess something went wrong here. Yes you can delete the sample index as well as disable or delete the sample app at
Keep in mind that the
sample_app will be re-installed by the installer whenever you upgrade splunk. So instead of deleting the app, I suggest disabling it. That preference will persist even after a new version of splunk has been installed; but if you remove the app, it will be installed again in an "enabled" state.