i am a little bit unclear on why you suggest to backup the Database schema but not all the data here:
First, you state:
"Database stores all information on the build results"
And then comes:
"If you use external database, please back up your database schema used by TeamCity."
Shouldn't it rather be:
"If you use external database, please back up your database schema and data used by TeamCity."
best regards // Dimitri