[Zope] Pack Zodb problem

Hi all, Every time I use the pack Zodb option, ZOPE creates a ZODB backup file. My Zodb is currently 2.1GB in size. To pack ZODB I will require around 2 GB of additional space in the server which i am unable to spare. Hence the pack command is failing. Is there any way to pack ZODB without creation of backup file? Regards, - sree