When you change the mailbox limits for a database these changes don’t take effect immediately.
This is because the information store uses cached information to apply these limits.
So, restarting the the IS will cause your new limits to be applied, but this isn’t exactly practical on a production environment.
By default the IS refreshes this cached information every two hours, but you can change this interval to suit you needs.
It should be noted that making these registry changes still needs the information store to be restarted, but once you have a different interval confiured, changes will be applied more regularly and the IS will not require future restarts.
Locate the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem key
Create a new DWORD value named Reread Logon Quotas Interval
Enter a Decimal value in seconds, the default value is two hours (7200 seconds), the recommended value is 20 minutes (1200 seconds), and then click OK.
Restart the IS