DBTab was an add-on product by Shane Hathaway for Zope 2.6 that allowed you to configure "mounted" databases in Zope. "Mounted" databases are separate ZODB databases that appear in the ZMI as normal folders, though they store their data in a completely different ZODB database. This is now built in to Zope 2.7. You configure it with zope_db sections in zope.conf.
http://www.plope.com/Members/chrism/whatsnew_27 - more details and configuration examples
APIDocs:DBTab.html
how to use with ZEO ? --simon, Sat, 17 Apr 2004 17:37:29 -0700 reply
Do you configure mount points in zeo.conf or in zope.conf ? I suspect the latter.