Two questions:
1- How big is your SQL Server database?
2- Do you need near-real-time extracts to DB2 or a daily snapshot would suffice?
Depending on answers I would consider either restoring a production backup as "reporting" or go for transactional replication.
Last but not least... what do you consider "heavy transactional database"?
_____________________________________
Pablo (Paul) Berzukov
Author of Understanding Database Administration available at Amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.