ORA-01618

ORA-01618: redo thread 2 is not enabled - cannot mount

Example

SQL> startup

ORACLE instance started.
 
Total System Global Area 4731174912 bytes
Fixed Size                  2061264 bytes
Variable Size             838863920 bytes
Database Buffers         3875536896 bytes
Redo Buffers               14712832 bytes
ORA-01618: redo thread 2 is not enabled - cannot mount

 

Details:

The above error will be displayed during the startup of a node in a rac cluster 

in the event that a redo thread is not enabled. You need to enable the thread 

instance prior to adding a redo log thread which is created using the 

            ALTER DATABASE ADD LOGFILE THREAD [NUMBER]

The respective instance threads can be identified from the init parameter files

below e.g.:

RACNODE1.THREAD=1  # RACNODE1 instance uses Thread 1
RACNODE2.THREAD=2  # RACNODE2 instance uses Thread 2

Solution:

Enabled the Thread on the active node as follows:

 

SQL> alter database enable public thread 2;
 
SQL> select thread#, enabled from v$thread;
 
   THREAD# ENABLED
---------- --------
         1 PUBLIC
         2 PUBLIC

Restart the node which displays the ORA error