Question : Windows 2003R2 Active Directory Domain Controllers

Hello,
We have one Active Directory domian ( no sub-domain ) with two domain controllers.
Both DCs are on Windows 2003 R2 Standard SP2 x64 and they are physically located on the same VLAN.
My expectation was two DCs coordinate roles dynamically/automatically so that one DC failure at any given time doesn't cause any issue in production.
However, that is not what is being witnessed in production.
We had to restart both DCs one at a time for maintenance purpose.
There was enough interval ( 30 min ) between reboot of each DC.
When DC1 was rebooting, all domain authentication seemed to failed.
For example, any application with Windows integrated security stopped working until the workstations are restarted.
Domain users network file server access failed also.

Basically, users had to reauthenticate to the domain during DC1 reboot and probably they were authenticated back to domain via DC2.

Is this a normal behavior of AD and DCs?
Or, our DCs are not properly configured?

Thank you for your help,

Answer : Windows 2003R2 Active Directory Domain Controllers

Sorry Experts... I found the solution elsewhere.

For your reference, here is the link to it...
http://www.visualstudiodev.com/visual-basic-express-edition/trying-to-debug-receive-requested-operation-requires-elevation-48897.shtml

This is the part that helped me...

Does you application have the words "setup",  "update", "install", or any of the other key phrases that Vista uses in  its heuristics to identify setup programs? If so, you don't need to run  Visual Studio as an administrator. You just need to either change the  name of your program or add a manifest file (which is difficult under VS  2005 editions) and mark it so that Vista UAC doesn't perform heuristics  testing on it.

The name of my app had the word Update in it...

Thank to anyone that was trying to find a solution for me.

Take care!