Global Catalogue should also be in Additional DC ?

It depends upon ur set up where is Addtional Domain controller located is it in the same site or Different site ? is primary Domain controller has role of Infrasture mater,???

Depends on your deployment plan What is the propose of ADC, where it is Located. I think your case you should have GC on ADC assuming that you are using It for HA. Thanks!

Hi,

Yes you must make the second DC as Global Catalog if you do not have GCs in other sites, in any environment there hould be at least two GCs, why, supose the Primary DC which is Global Catalog is down, in this case you if there is no other GC then this will make problems in AD.

HTH

Best Regards,

Actually it is not recommeded that GC & infrastructure Master role should be on the same server as GC contains complete & updated information of directory objects of it's parent doamin & partial information of other domain within the forest, & Infrastructure Master trying to get updated directory objects information from GC so if you keep both role on the same server then your infrastructure Master role will not work as IM will never find data that is outdated, so it will never replicate any changes to the other domain controller in the domain. So MS recommend that do not keep the both role on the same server until you have only single DC in your forest.

When you install AD DS, the global catalog for a new forest is created automatically on the first domain controller in the forest. You can add global catalog functionality to additional domain controllers. You can also remove the global catalog from a domain controller 

It can be depends on what you wants to do.

No, It is not necessary

NO it is not compulsory but it is recommended

Firt of all please note global catalog server will always be a DC. However a DC may or may not be globel catalog server.

Most of the times in less complex environments, one can have global catlog on all domain controllers. But in case of complex multi site or multi domain environment you should choose carefully according to your design.

No

Use GC for recovery and domain purpose. If your environment looking multidomain, use all the components with different servers.