FogBugz stores all the data it needs to run in the database. If you’re running FogBugz On Site, these are your “trialN” database(s). For FYS, the database is called “fogbugz” by default. If you’ve backed up this database, you’ve backed up FogBugz. Here are instructions on how to back up that database depending on how you have FogBugz installed and what type of database you are using:

Microsoft SQL Server

Microsoft has a knowledge base article on how to back up your SQL Server database. Make sure that every time you do a backup you are shrinking the transaction logs to keep them small.

You can find the physical server(s) hosting your database(s) by using the fbhosted database, the location of which is stored as sFBHostedConnectionString in the registry at HKEY_LOCAL_MACHINE\SOFTWARE\Fog Creek Software\FogBugz\<your fogbugz install directory>/Website. Run the following query on the fbhosted database:

SELECT t.ixFogBugzTrial, t.sUniqueSiteName, s.sSQLServerInstance, CONCAT('trial', t.ixFogBugzTrial) AS sDatabase
FROM tblFogBugzTrial t
  JOIN tblFogBugzTrialDBServerMap m ON t.ixFogBugzTrial = m.ixFogBugzTrial
  JOIN tblFogBugzTrialDBServer s ON m.ixFogBugzTrialDBServer = s.ixFogBugzTrialDBServer

In FogBugz FYS, the database details are available under Admin->Site->Database tab.

MySQL

If you’re running MySQL, you’re running FogBugz For Your Server. MySQL has a knowledge base article on how to back up your MySQL database. You can find the physical server your database is on by looking under Admin->Site->Database tab in FogBugz.