Killerbananas,
Thanks for your reply but i didn't realise i had already asked the question on a different thread and got the following response:-
You are correct in the fact that a Global Catalog Server primarily processes logons. If you want both of the DCs to be GCs, then that is perfectly fine. It will prove useful if one DC is rebooted or perhaps unavailable. Having multiple GCs is essentially like having multiple DNS Servers, or DHCP Servers, or Print Servers....It's all about the uptime!
Ryan Patel
Sr. Network Engineer|BS|MCSE|CCNA
The only thing to do with good advice is pass it on. It is never any use to oneself.