How many objects can an Active Directory (AD) instance store?

A. Eric Fleishman recently answered this questioned armed with a 64-bit Active Directory Application Mode (ADAM) instance and some custom scripts to create objects. He found that the theoretical limit of 2^31 objects was very close, filling the directory service just shy of 2^31 objects and hitting a clean error condition.

This result should hold comfort for those of us concerned that our databases might fill up. For more information about Fleishman's testing, visit http://blogs.technet.com/efleis/archive/2006/06/08/434255.aspx .