I recently changed the mailbox quota limits on my Exchange 2000 Server machine, but the new limits didn't take effect for almost an hour. Why did the change take so long?
In Exchange 2000, the quota limits are attributes of Active Directory (AD) objects. Therefore, when you change the quota, Exchange tags the object as modified, then a background maintenance thread makes the change. In addition, after the change has been made on one AD Global Catalog (GC), you might also have to wait for the change to be replicated throughout your AD forest. Restarting the Information Store (IS) forces the change to occur immediately because that action forces the background maintenance thread to restart. However, this approach is gross overkill—it takes all your users offline, and all you get in return is a minor speedup in quota application times. By default, that thread runs every 60 minutes; if you make a quota change right after the thread has finished, you'll have to wait almost an hour for it to run again, which is probably the root cause of your problem. If you want to change the interval at which the thread runs, see the Microsoft article "XADM: Storage Quota Takes Up to 60 Minutes to Update" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q280498) for instructions.