ORA-38856: Cannot mark instance UNNAMED_INSTANCE_2 (redo thread 2) as enabled

 

ORA-38856: Cannot mark instance UNNAMED_INSTANCE_2 (redo thread 2) as enabled

Example:

In the example below the error Occurred while performing an open resetlogs on a 10.2.0.3 Oracle Single Instance Database
Server prior to restoring an RMAN backup of and Oracle Database. The RMAN backup was taken from a RAC Database Server
and restored to a Single Instance Box.

SQL> alter database open resetlogs;

alter database open resetlogs
*
ERROR at line 1:
ORA-38856: cannot mark instance UNNAMED_INSTANCE_2 (redo thread 2) as enabled

Details:

ORA-38856: cannot mark instance UNNAMED_INSTANCE_2 (redo thread 2) as enabled.


Oracle bug, 4355382 ORA-38856: FAILED TO OPEN DATABASE WITH RESETLOGS WHEN USING RAC BACKUP, exists in the
Oracle 10g release 2.0 that affects backups taken from a RAC database. The problem is related to the number of threads
used by the source database and an expectation that the cloned database must have an identical number of threads.


Solution:

1. Set the following parameter in the auxiliary init.ora file: _ no_recovery_through_resetlogs=TRUE.

2. Open the database in resetlogs mode.

3. Remove _ no_recovery_through_resetlogs=TRUE from init.ora.

4. Restart database.