How to modify the replication interval between Domain controllers in different sites to less than 15 minutes?

I recently came across a problem where DCs in our two data centers (Each datacenter is a different AD site) were not replicating fast enough. Because the DCs in question are in different sites, the minimum interval for replication between sites can only be 15 minutes, which is not good enough for us. So the workaround is to set the ADSI attribute “options” for the site link to 1 which means USE_NOTIFY attribute.

USE_NOTIFY forces the replication to occur when a change is made. But this does not work on manually created connections like we have. It only works on connections managed and created by KCC (these connections will have the value “automatically generated” shown under the first column. (details can be found at http://blogs.msdn.com/b/canberrapfe/archive/2012/03/26/active-directory-replication-change-notification-amp-you.aspx)

So what worked in our case to force the servers to override the default values by using integer value 12 for each server’s NTDS settings in ADSI. Details are in http://www.ryanjadams.com/2010/05/turbo-charge-active-directory/#axzz2PaGkqbUu. I have modified the attribute “options” for each server

a.       Open ADSI edit

b.      Connect to and expand the Configuration container

c. Navigate to Sites-> Sitename-> Servers-> servername-> NTDS Settings

d. Right click and select properties for each manual connection object in this folder.

e. Select the “Options” property.  Note that if the value is 1 then it is an intrasite connection object and owned by the KCC.  If the value is 5 then it is an intersite connection object and owned by the KCC.  If it is one of these values and owned by the KCC then do NOT change it.  It should be changed at the site level instead, otherwise if you change the value on a connection object that is owned by the KCC you force it out of KCC control and the KCC will no longer manage it.

f. In the edit attribute box, change the value to 12.