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How to Enable Archivelog Mode On RAC 10g/11g/12c

This article highlights the differences between resetting the archive log mode on a single node instance and a Real Application Clusters (RAC).

Single Instance

Oracle 9i

On a single node 9i instance the archive log mode is reset as follows.
ALTER SYSTEM SET log_archive_start=TRUE SCOPE=spfile;
ALTER SYSTEM SET log_archive_dest_1='location=/u01/oradata/MYSID/archive/' SCOPE=spfile;
ALTER SYSTEM SET log_archive_format='arch_%t_%s.arc' SCOPE=spfile;

SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ARCHIVE LOG START;
ALTER DATABASE ARCHIVELOG;
ALTER DATABASE OPEN;

Oracle 10g Upward

In Oracle 10g the LOG_ARCHIVE_START parameter and ARCHIVE LOG START command have been deprecated, so you will use the following code.
ALTER SYSTEM SET log_archive_dest_1='location=/u01/oradata/MYSID/archive/' SCOPE=spfile;
ALTER SYSTEM SET log_archive_format='arch_%t_%s_%r.arc' SCOPE=spfile;

SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER DATABASE ARCHIVELOG;
ALTER DATABASE OPEN;

Real Application Clusters (RAC)

The ALTER DATABASE ARCHIVELOG command can only be performed if the database in mounted in exclusive mode. This means the whole clustered database must be stopped before the operation can be performed.

Oracle 9i

First we set the relevant archive parameters.
ALTER SYSTEM SET log_archive_start=TRUE SCOPE=spfile;
ALTER SYSTEM SET log_archive_dest_1='location=/u01/oradata/MYDB/archive/' SCOPE=spfile;
ALTER SYSTEM SET log_archive_format='arch_%t_%s.arc' SCOPE=spfile;
Since we need to mount the database in exclusive mode we must also alter the following parameter.
ALTER SYSTEM SET cluster_database=FALSE SCOPE=spfile;
From the command line we can stop the entire clustered database using the following.
$ srvctl stop database -d MYDB
With the cluster down we can connect to a single node and issue the following commands.
STARTUP MOUNT;
ARCHIVE LOG START;
ALTER DATABASE ARCHIVELOG;
ALTER SYSTEM SET cluster_database=TRUE SCOPE=spfile;
SHUTDOWN IMMEDIATE;
Notice that the CLUSTER_DATABASE parameter has been reset to it's original value. Since the datafiles and spfile are shared between all instances this operation only has to be done from a single node.
From the command line we can now start the clustered database again using the following.
$ srvctl start database -d MYDB
The current settings place all archive logs in the same directory. This is acceptable since the thread (%t) is part of the archive format preventing any name conflicts between instances. If node-specific locations are required the LOG_ARCHIVE_DEST_1 parameter can be repeated for each instance with the relevant SID prefix.

Oracle 10gR1

If the LOG_ARCHIVE_DEST_n parameters are not set, the archived redo logs will be placed in the FRA. If you want to specify their location and the file name format manually, you can do it as follows.
ALTER SYSTEM SET log_archive_dest_1='location=/u01/oradata/MYDB/archive/' SCOPE=spfile;
ALTER SYSTEM SET log_archive_format='arch_%t_%s_%r.arc' SCOPE=spfile;
Since we need to mount the database in exclusive mode we must also alter the following parameter.
ALTER SYSTEM SET cluster_database=FALSE SCOPE=spfile;
From the command line we can stop the entire clustered database using the following.
$ srvctl stop database -d MYDB
With the cluster down we can connect to a single node and issue the following commands.
STARTUP MOUNT;
ALTER DATABASE ARCHIVELOG;
ALTER SYSTEM SET cluster_database=TRUE SCOPE=spfile;
SHUTDOWN IMMEDIATE;
Notice that the CLUSTER_DATABASE parameter has been reset to it's original value. Since the datafiles and spfile are shared between all instances this operation only has to be done from a single node.
From the command line we can now start the clustered database again using the following.
$ srvctl start database -d MYDB

Oracle 10gR2

From 10gR2, you no longer need to reset the CLUSTER_DATABASE parameter during the process.
If the LOG_ARCHIVE_DEST_n parameters are not set, the archived redo logs will be placed in the FRA. If you want to specify their location and the file name format manually, you can do it as follows.
ALTER SYSTEM SET log_archive_dest_1='location=/u01/oradata/MYDB/archive/' SCOPE=spfile;
ALTER SYSTEM SET log_archive_format='arch_%t_%s_%r.arc' SCOPE=spfile;
From the command line we can stop the entire clustered database and start it in mount mode using the following.
$ srvctl stop database -d MYDB
$ srvctl start database -d MYDB -o mount
With the database mounted issue the following commands.
sqlplus / as sysdba

ALTER DATABASE ARCHIVELOG;
EXIT;
Since the datafiles and spfile are shared between all instances this operation only has to be done from a single node.
From the command line we stop and start the clustered database again using the following commands.
$ srvctl stop database -d MYDB
$ srvctl start database -d MYDB

Oracle 11g

The process is exactly the same in 11g as in the previous Oracle 10gR2 section.

Oracle 12c


The process is exactly the same in 12c as in the previous Oracle 10gR2 section.

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