Database Software

Dear Oracle Experts,

I will describe the high availability architecture that I have mounted in a test environment:

- In Main building (MB):
I have a cluster linux RHEL 5.4 server1 and server2, oracle is installed on each server with a shared
filesystem that stores the database. So the database (sid, listener, filesystem) is in one node and if this node
down the database (sid, listener, filesystem) migrate and another node.

- In Disaster Recovery building (DRB):
The same architecture with cluster linux and besides physical Data Guard between primary-database (in main
building) and standby database (in DRB).

I have some questions about that:
- I have configured data guard broker, but if my database in MB building migra from node1 to node2
dgmgrl configuration have this errors:

ORA-16603: Data Guard broker detected a mismatch in configuration ID
ORA-16625: cannot reach the database
DGM-17017: unable to determine configuration status

- Where can i configure obsever process? In a three different server?
If start observer process:
DGMGRL> start observer;
Observer started

Can i close this session? Because hours later the observer is stop, and i don't why.
HOw i start observer with scritp?

- With observer configured and fast start failover, if in database1, node1 (MB) do shutdown abort
a oracle start standby database automatically or i have to do manual process?


- This architecture is correct? or i can problems if down server1 (MB) the database migra to node2 in (MB) or
to node1 (DRB)?

Is my first time that i configure physical dataguard and i have many doubts