[Zope] storing in ZODB vs filesystem

Hi, I need to have a document management system. That would involve a lot of document upload. Can some one advice me on whether its wise to store all the documents as zope does by default into the database or store the file on to some place in the file system. Can someone tell me how to do this easily ! If it profitable to do that ? I have a feeling that storing all the documents in the database might slow down the database! thanks, Ciji Isen