The reason for the Broker-pers to grow faster than usual is due to use of Document Types and Client Groups. Creating them as Persistent storage instead of Guaranteed or Volatile causes this problem.
Going forward with newer versions of Enterprise Server, the storage type is either volatile of guaranteed.
Make sure that none of the Client Groups and Document Types have been defined as persistent.
This should solve your problem.
To understand more about how storage type works, please read the Admin Analysis Guide, Chapter 3 - Setting up Client Groups and read section on Client Queue Storage versus Document Type Storage.
#webMethods#Integration-Server-and-ESB