I'm currently studying for OCP certification exam 1z0-053.
For this I bought the All-in-One Exam Guide from Oracle Press (http://www.mcgrawhill.ca/professional/products/9780071629188/)
While studying, I like to test, prove things and simulate operation to get more familiar as possible with important concepts.
The study guide covers the fact that when a critical file is damaged or lost, the instance will terminate. Listed critical files are : any copy of controlfile, a datafile that is part of the SYSTEM tablespace, a datafile that is part of the current undo tablespace.
As said here is the quote:
Some files are critical. Damage to a critical file will mean that the database instance will terminate if it is open, and cannot be reopened until the damage is repaired.
Virtually the moment the damage occurs, the instance will terminate. As ever, the DBA’s first reaction to a crashed instance should be to attempt a startup. This will fail, in NOMOUNT mode, with an appropriate error message. The alert log will state which controlfile copy is missing, and also—in the section listing the nondefault initialization parameters—how many controlfile copies there actually are, and where they are.
In a end-of-chapter self test there is a question:
1. Loss of which of these files will cause an open database to crash? (Choose all correct answers.)
A. A multiplexed controlfile
B. A multiplexed online log file
C. A multiplexed archive log file
D. An active undo tablespace datafile
E. An active temporary tablespace tempfile
F. A datafile from the SYSAUX tablespace
G. A datafile from the SYSTEM tablespace
H. A datafile containing critical user data
1. A, D, and G. Damage to any controlfile copy will terminate the instance, as will damage to the critical tablespaces: SYSTEM and the current undo tablespace.
So, under 18.104.22.168 when I delete or corrupt a control file copy, the instance isn't crashing and the database continue to be working. Only alert log is regularly notifynig the controlfile missing:
Fri Aug 30 10:16:02 2013
Errors in file /u01/app/oracle/diag/rdbms/ocp1/ocp1/trace/ocp1_m000_26767.trc:
ORA-00210: cannot open the specified control file
ORA-00202: control file: '/u01/app/oracle/oradata/ocp1/control03.ctl'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
I'm not really undestanding.
Do I need to stick on what is said in the book or the experienced facts?