That depends on how many clients you have and what data you are storing.
when clients send logs, that DB will grow. Check this guide.
http://service1.symantec.com/SUPPORT/ent-security.nsf/383ed085ad1ed2c6882571500069b34d/18873ad6514d93b2882576cc0065df54/$FILE/SEP%20Sizing%20and%20Scalability%20Best%20Practices_%20v2.1_Final.pdf