if we have the case where we lost the rollback segment datafiles for examplyas follow:

1. the database crashed or shutdown abort
2. del rbs1orcl.ora
3. copy backup\rbs1orcl.ora
4. in init.ora ---> comment out the ROLLBACK_SEGMENTS
5. startup mount
6. alter database datafile 'c:\oradata\rbs1orcl.ora' offline;
7. alter database open.


two questions:
1. even I comment out the ROLLBACK_SEGMENTS out so I thought Oracle won't find the existing rollback segments but I think it's still use the existing rollback_segments
2. on number 7, when I tried to open the database, even I took the missing datafile offline, but it still looks for that file and the database couldn't open.

please advise