[Zope] ZEO and Multiple Zope Sites

We're testing and upgrade from ZOPE 2.3.3 > ZOpe 2.5.1 with ZEO running We're having good success with both with only in Test environment (minimal users) Possible 3000 users hit Production ZServers Possible future problem. 1. Web site growth will cause Data.fs to become too large Solutions??? ? Mounting ZODB(s) Bottom line is... How do I prevent a meltdown of these present web sites when/if content too much for one ZServer to handle? Any and all suggestion will be gratefully accepted Eric Dunn