[Zope] How to disable ZODB transaction.

Hi zopistas, I'm developing an site that has a few thousands of transactions per day. The site adds and deletes a lot of DTML Documents. The ZODB grows dramatically and when I pack manually the database it consumes a lot of time. Is there a way to disable the transactions persistence in ZODB? When not, how can I invoke a "pack" from a python script to call it periodically with a cron job?