RMAN-06169: could not read file header for datafile 7 error reason 9

Error
While attempting to run a backup of the database, we got an error identifying a problem with a datafile. In this post, I will discuss the cause of the problem and how the error was resolved.

rman target sys/****@PUBLIC

Starting backup at 01-APR-13
using channel ORA_DISK_1
RMAN-06169: could not read file header for datafile 7 error reason 9
RMAN-06169: could not read file header for datafile 7 error reason 9
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 04/01/2013 15:54:32
RMAN-06056: could not access datafile 7

cause
There is a problem with the datafile 7. It could be due to corruption, or any other problem with the datafile. Oracle will not be able to back up the database except this datafile is restored. Alternative, as a temporary solution, you can skip the datafile in your backup. If the datafile is skipped, RMAN will be able to back up the database but it is not advisable.


solution:

Check the status of the datafile
sqlplus sys/***@PUBLIC

SQL> select file#, status from v$datafile where file# = 7;
FILE# STATUS
---------- -------
7 RECOVER

SQL> select file#, status, enabled from v$datafile where file# = 7;
FILE# STATUS ENABLED
---------- ------- ----------
7 RECOVER READ WRITE
exit;

Restore the datafile from backup
A copy of the datafile in backup can be used to restore the datafile. Simply log back into rman and issue this command:
RMAN> restore datafile 7;
datafile restored

NOTE: You do not need to put your database in mount mode to do this.

Recover the datafile
Recovering a datafile after restore brings it up to date. At this stage, archivelogs and incremental backups will be applied to bring the datafile to the point it was before the problem.

RMAN> recover datafile 7;
starting media recovery
database recovered


For more details on RMAN recovery and restore process, check out Oracle documentations at RMAN