Real Time Log Apply on Standby Database

 

              Configure Real Time Log Apply on Standby

By default, log apply services wait for the full archived redo log file to arrive on the standby database before applying it to the standby database. If the real-time apply feature is enabled, log apply services can apply redo data as it is received from the Primary DB, without waiting for the current standby redo log file to be archived. We can use the ALTER DATABASE statement to enable the real-time apply feature, as below:

• For physical standby databases, issue the ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE statement.

• For logical standby databases, issue the ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE statement.

NOTE : Standby redo log files are required to use real-time apply.


Lets Test it:

oracle@ORCLSTDBY:[~] $ sqlplus /"as sysdba"

SQL*Plus: Release 11.2.0.4.0 Production on Tue Oct 4 10:57:52 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> recover managed standby database cancel;
Media recovery complete.

SQL> select dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;

DEST_NAME            STATUS     TYPE       SRL RECOVERY_MODE
-------------------- ---------- ---------- --- ------------------------------
LOG_ARCHIVE_DEST_1   VALID      LOCAL      NO  IDLE

-- Dest_id can be different in your database. but mostly it will be set to local.
-- Lets start applying logs and start the recovery mode Default (apply on log fill up)

SQL> recover managed standby database disconnect from session;
Media recovery complete.

-- Query the Recovery Mode now:

SQL> col DEST_NAME format A20
col status format A10
col type format A10
col recovery_mode format A30

select dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;

DEST_NAME            STATUS     TYPE       SRL RECOVERY_MODE
-------------------- ---------- ---------- --- ------------------------------
LOG_ARCHIVE_DEST_1   VALID      LOCAL      NO  MANAGED

-- See that Recovery Mode will be just Managed. 

-- Lets stop log Apply and change it the recovery mode to Real-Time Apply

SQL> recover managed standby database cancel;
Media recovery complete.

SQL> alter database recover managed standby database using current logfile disconnect from session;

Database altered.

SQL> select dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;

DEST_NAME                       STATUS      TYPE       SRL        RECOVERY_MODE
--------------------                   ----------       ----------     ---          ------------------------------
LOG_ARCHIVE_DEST_1   VALID      LOCAL   NO  MANAGED REAL TIME APPLY


-- We can also check this in alertlog_File.log


Completed: ALTER DATABASE RECOVER  managed standby database cancel
Tue Oct 04 11:00:47 2016
.
.
alter database recover managed standby database using current logfile disconnect from session
Attempt to start background Managed Standby Recovery process (ORCLSTDBY)
Tue Oct 04 11:00:47 2016
MRP0 started with pid=58, OS id=40557
MRP0: Background Managed Standby Recovery process started (ORCLSTDBY)
 started logmerger process
Tue Oct 04 11:00:52 2016
Managed Standby Recovery starting Real Time Apply
Parallel Media Recovery started with 64 slaves
Waiting for all non-current ORLs to be archived...


Reference Oracle Docs:

https://docs.oracle.com/cd/B19306_01/server.102/b14239/log_apply.htm#i1034632


 Similar Posts :

• How to add second standby database 
• How to create Standby database using RMAN
• Open Standby Database in Read-Only  
• Find Archive Gap between Primary and Standby Database

CHANGE STANDBY DATABASE PROTECTION MODE

SQL> select protection_mode from v$database;

PROTECTION_MODE
--------------------
MAXIMUM PERFORMANCE

SQL> show parameter log_archive_dest_2

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2             string     SERVICE=ORCLSTB1 NOAFFIRM ASYN
                         C VALID_FOR=(ONLINE_LOGFILES,P
                         RIMARY_ROLE) DB_UNIQUE_NAME=OR
                         CLSTB1
log_archive_dest_20             string
log_archive_dest_21             string
log_archive_dest_22             string
log_archive_dest_23             string
log_archive_dest_24             string
log_archive_dest_25             string
log_archive_dest_26             string

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_27             string
log_archive_dest_28             string
log_archive_dest_29             string
SQL> show parameter db_unique_name

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                 string     ORCL
SQL> show parameter log_archive_config

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
log_archive_config             string     dg_config=(ORCL,ORCLSTB1,ORCLS
                         TB2)
SQL> alter system set log_archive_dest_2='SERVICE=ORCLSTB1 NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB1';

System altered.

SQL> show parameter log_archive_dest_2

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2             string     SERVICE=ORCLSTB1 NOAFFIRM ASYN
                         C VALID_FOR=(ONLINE_LOGFILES,P
                         RIMARY_ROLE) DB_UNIQUE_NAME=OR
                         CLSTB1
log_archive_dest_20             string
log_archive_dest_21             string
log_archive_dest_22             string
log_archive_dest_23             string
log_archive_dest_24             string
log_archive_dest_25             string
log_archive_dest_26             string

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_27             string
log_archive_dest_28             string
log_archive_dest_29             string

SQL> alter system set log_archive_dest_2='SERVICE=ORCLSTB1 NOAFFIRM SYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB1';

System altered.


SQL> alter database set standby database to maximize availability;

Database altered.

NOTE: You don’t need to shutdown your instance, when you are changing  protection mode from MAXIMUM PERFORMANCE TO MAXIMUM AVAILABILITY.But you need to if you are going to MAXIMUM PROTECTION.

SQL> alter system switch logfile;

System altered.

SQL> select protection_mode from v$database;

PROTECTION_MODE
--------------------
MAXIMUM AVAILABILITY

SQL> archive log list;
Database log mode           Archive Mode
Automatic archival           Enabled
Archive destination           /u01/app/oracle/oraarch/
Oldest online log sequence     239
Next log sequence to archive   241
Current log sequence           241
SQL> select group#,bytes/1024/1024 from v$standby_log;

    GROUP# BYTES/1024/1024
---------- ---------------
     4        52
     5        52
     6        52
     7        52


SQL> select thread#,max(sequence#) from v$archived_log group by thread#;

   THREAD# MAX(SEQUENCE#)
---------- --------------
     1          240

SQL> select protection_mode from v$database;

PROTECTION_MODE
--------------------
MAXIMUM AVAILABILITY



SQL> alter system switch logfile;

System altered.

ENABLE REAL TIME APPLY ON STANDBY DATABASE

*********************************************************************
    REAL TIME APPLY OF ARCHIVE LOG FILES IN READ ONLY MODE:
*********************************************************************

SQL> select PROTECTION_MODE,PROTECTION_LEVEL FROM V$DATABASE;

PROTECTION_MODE      PROTECTION_LEVEL
-------------------- --------------------
MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

SQL> archive log list;
Database log mode           Archive Mode
Automatic archival           Enabled
Archive destination           /u01/app/oracle/oraarch/
Oldest online log sequence     250
Next log sequence to archive   0
Current log sequence           252

SQL> recover managed standby database using current logfile disconnect from session;
Media recovery complete.
SQL> alter database open read only;

Database altered.


***********************************************************************************
    NOW ON PRIMARY DATABASE I CREATE TABLE IN ONE OF USER ADD INSERT SOME DATA
***********************************************************************************

[oracle@Linux01 Desktop]$ sqlplus /"As sysdba"

SQL> select name,open_mode,db_unique_name,PROTECTION_MODE,PROTECTION_LEVEL FROM V$DATABASE;

NAME          OPEN_MODE                   DB_UNIQUE_NAME   PROTECTION_MODE        PROTECTION_LEVEL
--------     --------------------    ---------         --------------------         ---------
ORCL          READ ONLY WITH APPLY     ORCLSTB1        MAXIMUM PERFORMANCE      MAXIMUM PERFORMAN



SQL> conn atoorpu/XXXXX;
Connected.
SQL> create table abcd (name varchar2(20));

Table created.

SQL> insert into abcd values ('arvind');

1 row created.

SQL> commit;

Commit complete.


SQL> alter system switch logfile;

System altered.

SQL> insert into abcd values ('reddy');

1 row created.

SQL> commit;

Commit complete.

SQL> create table abcds as select * from abcd;

Table created.

***********************************************************************************
    NOW ON STANDBY DATABASE LETS QUERY SAME DATA SOME DATA
***********************************************************************************

[oracle@Linux02 Desktop]$ sqlplus /"As sysdba"

SQL> select name,open_mode,db_unique_name,PROTECTION_MODE,PROTECTION_LEVEL FROM V$DATABASE;

NAME          OPEN_MODE                   DB_UNIQUE_NAME   PROTECTION_MODE        PROTECTION_LEVEL
--------     --------------------    ---------         --------------------         ---------
ORCL          READ ONLY WITH APPLY     ORCLSTB1        MAXIMUM PERFORMANCE      MAXIMUM PERFORMAN

SQL> conn atoorpu/XXXXX;
Connected.
SQL> select * from abcd;

NAME
--------------------
arvind

SQL> select * from abcd;

NAME
--------------------
arvind
reddy

OPEN STANDBY DATABASE IN READ ONLY

SQL> select PROTECTION_MODE,PROTECTION_LEVEL FROM V$DATABASE;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

SQL> select name,db_unique_name,open_mode,DATABASE_ROLE from v$database;

NAME   DB_UNIQUE_NAME  OPEN_MODE       DATABASE_ROLE

--------- ------------------------------ -------------------- ----------------

ORCL   ORCLSTB1  MOUNTED       PHYSICAL STANDBY

 SQL> alter database open read only;

Database altered.

SQL> select name,db_unique_name,open_mode,DATABASE_ROLE from v$database;

NAME   DB_UNIQUE_NAME  OPEN_MODE       DATABASE_ROLE

--------- ------------------------------ -------------------- ----------------

ORCL   ORCLSTB1  READ ONLY       PHYSICAL STANDBY

SQL> select PROTECTION_MODE,PROTECTION_LEVEL FROM V$DATABASE;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM AVAILABILITY MAXIMUM AVAILABILITY

SQL> SELECT database_role, open_mode FROM v$database;

DATABASE_ROLE  OPEN_MODE

---------------- --------------------

PHYSICAL STANDBY READ ONLY WITH APPLY

SQL> select process,status from v$managed_standby;

PROCESS   STATUS
--------- ------------
ARCH      CLOSING
ARCH      CLOSING
ARCH      CONNECTED
ARCH      CLOSING
ARCH      CLOSING
RFS      IDLE
RFS      IDLE
RFS      IDLE
RFS      IDLE
MRP0      APPLYING_LOG
 


 Similar Posts :

• How to add second standby database 
• How to create Standby database using RMAN
• Open Standby Database in Read-Only  
• Find Archive Gap between Primary and Standby Database

database switch over using dgmgrl

Perform a switch over test:


ON PRIMARY DB SERVER :

SQL> select name,open_mode,db_unique_name ,DATABASE_ROLE from v$database;

NAME  OPEN_MODE       DB_UNIQUE_NAME      DATABASE_ROLE
--------- -------------------- ------------------------------ ----------------
ORCL  READ WRITE       ORCL      PRIM

ON STANDBY DB SERVER :

SQL> select name,open_mode,db_unique_name ,DATABASE_ROLE from v$database;

NAME  OPEN_MODE       DB_UNIQUE_NAME      DATABASE_ROLE
--------- -------------------- ------------------------------ ----------------
ORCL  MOUNTED       ORCLSTB1      PHYSICAL STANDBY


LETS CONNECT TO DGMGRL AND SWITCH OVER ROLES

DGMGRL> switchover to 'ORCLSTB1';
Performing switchover NOW, please wait...
Operation requires a connection to instance "ORCLSTB1" on database "ORCLSTB1"
Connecting to instance "ORCLSTB1"...
Connected.
New primary database "ORCLSTB1" is opening...
Operation requires startup of instance "ORCLPRIM" on database "ORCL"
Starting instance "ORCLPRIM"...
Unable to connect to database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Failed.
Warning: You are no longer connected to ORACLE.

Please complete the following steps to finish switchover:
start up and mount instance "ORCLPRIM" of database "ORCL"


ON OLD PRIMARY DB SERVER (ORCL) :

I have to start it manually coz dgmgrl was unable to connect to lsnr after role transfer.

SQL> startup mount;
ORACLE instance started.

Total System Global Area  885211136 bytes
Fixed Size    2258320 bytes
Variable Size  566233712 bytes
Database Buffers  310378496 bytes
Redo Buffers    6340608 bytes
Database mounted

SQL> select name,open_mode,db_unique_name ,DATABASE_ROLE from v$database;

NAME  OPEN_MODE       DB_UNIQUE_NAME      DATABASE_ROLE
--------- -------------------- ------------------------------ ----------------
ORCL  MOUNTED       ORCL      PHYSICAL STANDBY


LETS CONFIRM THE DB_ROLE BY QUERYING STANDBY DATABASE

SQL> select name,open_mode,db_unique_name ,DATABASE_ROLE from v$database;

NAME  OPEN_MODE       DB_UNIQUE_NAME      DATABASE_ROLE
--------- -------------------- ------------------------------ ----------------
ORCL  READ WRITE       ORCLSTB1      PRIMARY

RMAN-06820: WARNING: failed to archive current log at primary database

RMAN archive log backup at the standby site is throws the following errors

********************************************************************************
RMAN-06820: WARNING: failed to archive current log at primary database ORACLE error from target database: ORA-17629: Cannot connect to the remote database server
********************************************************************************


RMAN> backup database plus archivelog tag 'FULL_AL_BKP';


Starting backup at 29-FEB-16
RMAN-06820: WARNING: failed to archive current log at primary database
ORACLE error from target database:
ORA-17629: Cannot connect to the remote database server
ORA-17627: ORA-00942: table or view does not exist

allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=48 device type=DISK
skipping archived logs of thread 1 from sequence 192 to 201; already backed up
Finished backup at 29-FEB-16

Starting backup at 29-FEB-16
using channel ORA_DISK_1
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/ORCLSTB1/system01.dbf
input datafile file number=00002 name=/u01/app/oracle/oradata/ORCLSTB1/sysaux01.dbf
input datafile file number=00005 name=/u01/app/oracle/oradata/ORCLSTB1/example01.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/ORCLSTB1/undotbs01.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/ORCLSTB1/users01.dbf
channel ORA_DISK_1: starting piece 1 at 29-FEB-16
channel ORA_DISK_1: finished piece 1 at 29-FEB-16
piece handle=/u01/app/oracle/backup/ORCLSTB1/ORCL_20160229_82_1_1.bak tag=TAG20160229T114824 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
Finished backup at 29-FEB-16

Starting backup at 29-FEB-16
RMAN-06820: WARNING: failed to archive current log at primary database
ORACLE error from target database:
ORA-17629: Cannot connect to the remote database server
ORA-17627: ORA-00942: table or view does not exist

using channel ORA_DISK_1
specification does not match any archived log in the repository
backup cancelled because there are no files to backup
Finished backup at 29-FEB-16

Starting Control File and SPFILE Autobackup at 29-FEB-16
piece handle=/u01/app/oracle/backup/ORCLSTB1/c-1424488411-20160229-05 comment=NONE
Finished Control File and SPFILE Autobackup at 29-FEB-16


But rest of the backup actually completed successfully.

As per the Source : http://oraclesivaram.blogspot.com/2015/11/rman06820-warning-failed-to-archive.html

****************
CAUSE:
****************

11.2.0.4 onward as per 'unpublished' Bug 8740124, we now include the current standby redo log as part of an RMAN archivelog backup at the standby site. This is achieved by forcing a log switch at the primary site. However, the connection to the primary failed when attempting to do so.This is due to this bug:
Bug 17580082 ACTIVE STANDBY RMAN06820: WARNING: FAILED TO ARCHIVE CURRENT LOG AT PRIMARY

****************
Workaround:
****************
Do not use operating system authentication to login with RMAN. Use a username and password.

That is, do not use just the "/" (operating system authentication) connect to the standby database:
$ rman target /
Connecting as 'rman target /'

# it gets the sys user but not the password and so, it does NOT mean it is being explicitly specified to connect as sysdba.
Instead put in the username and password for the SYSDBA user:

$ rman target sys/password@stby
Connecting as 'rman target sysdba_user/password@stby'

Note: Also make sure password, within the (ORAPWD) password file, in primary and standby should be identical.

For more details please look at the Doc ID: 1616074.1

restore archive logs from backup

Restoring a archive log (LOG SEQ) from backups.

[oracle@Linux02 backups]$ rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Tue Feb 16 10:47:13 2016

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ORCL (DBID=1424488411, not open)

RMAN> restore archivelog logseq 140;

Starting restore at 16-FEB-16
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=32 device type=DISK

channel ORA_DISK_1: starting archived log restore to default destination
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=140
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/backup/rman_bak_ORCL_DB_0rqtvod6_27_1
channel ORA_DISK_1: piece handle=/u01/app/oracle/backup/rman_bak_ORCL_DB_0rqtvod6_27_1 tag=LEVEL0BACKUP_FORSTANDBY
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 16-FEB-16

Restoring archive from backups from SEQ. 

This will restore all archive logs from SEQ till date

RMAN> restore archivelog from logseq 140;   

Restoring archive from backups from SEQ until SEQ .

RMAN> restore archivelog from logseq 140 until logseq 150;

Starting restore at 16-FEB-16
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=35 device type=DISK

archived log for thread 1 with sequence 140 is already on disk as file /u01/app/oracle/oraarch/ORCLSTB1_1_140_896707677.arc
channel ORA_DISK_1: starting archived log restore to default destination
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=141
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=142
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=143
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=144
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=145
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=146
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=147
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=148
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=149
channel ORA_DISK_1: restoring archived log
archived log thread=1 sequence=150
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/backup/rman_bak_ORCL_DB_0rqtvod6_27_1
channel ORA_DISK_1: piece handle=/u01/app/oracle/backup/rman_bak_ORCL_DB_0rqtvod6_27_1 tag=LEVEL0BACKUP_FORSTANDBY
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 16-FEB-16

ORACLE FAL_CLIENT and FAL_SERVER explained

FAL_CLIENT and FAL_SERVER are initialization parameters used to configure log gap detection and resolution at the standby database side of a physical database configuration. This functionality is provided by log apply services and is used by the physical standby database to manage the detection and resolution of archived redo logs.

FAL_CLIENT and FAL_SERVER only need to be defined in the initialization parameter file for the standby database(s). It is possible; however, to define these two parameters in the initialization parameter for the primary database server to ease the amount of work that would need to be performed if the primary database were required to transition its role.


Sample setup:

In Primary site:

FAL_SERVER=STANDBY
FAL_CLIENT=PRIMARY

In Standby site:

FAL_SERVER=PRIMARY
FAL_CLIENT=STANDBY

Configure second physical standby database - Oracle

I know there are various cases where in we have to setup a second physical standby database in our environments to have a redundant fail over strategy. I don't think there are enough documents out there that outline the process of adding the second standby database. I though I will share these steps today.

Parameters that should be considered while setting up the 2 node (single instance) standby Database.
In my case I will explain the parameters and their usage in setup. I am not going to explain the entire setup here. I you don't know how to setup physical standby database, please refer to this Physical_standby_setup.

At this point I am considering you know how to setup physical standby database and you are looking to add additional node to your setup.

Environments:

ORCL is PRIMARY INSTANCE and is on host        LINUX01   >> Primary Instance
ORCLSTB1 is STANDBY INSTANCE and is on host LINUX02  >> Standby already exists
ORCLSTB2 is STANDBY INSTANCE and is on host LINUX03  >>>  new instance to be added

PARAMETERS to be considered :

ARCHIVE_LOG_DEST_N   >>> these needs to be set to ship your logs to the new node,

This is a simple setup that can be used to makes sure all the three nodes will ship logs in case of switch over. In the below image I have configured such a way that each instance will send log files to other when they act as PRIMARY INSTANCE.

Note : I am using round robin process to ship logs between DB servers.

Example of Archive_Log_Dest setup

Adding Archive_log Dests:

ON DB SERVER Linux01 (ORCLPRIM):

alter system set log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='SERVICE=ORCLSTB1 NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB1';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ENABLE;

ALTER SYSTEM SET LOG_ARCHIVE_DEST_3='SERVICE=ORCLSTB2 NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB2';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_3=ENABLE;

ON DB SERVER Linux02 (ORCLSTB1):

alter system set log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='SERVICE=ORCLPRIM NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCL';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ENABLE;

ALTER SYSTEM SET LOG_ARCHIVE_DEST_3='SERVICE=ORCLSTB2 NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB2';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_3=ENABLE;

ON DB SERVER Linux03 (ORCLSTB2):

alter system set log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='SERVICE=ORCLPRIM NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCL';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ENABLE;

ALTER SYSTEM SET LOG_ARCHIVE_DEST_3='SERVICE=ORCLSTB1 NOAFFIRM ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=ORCLSTB1';

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_3=ENABLE;

OTHER PARAMETER FILE SETTINGS: 

PFILE DB_* PARAMETERS on DB SERVER1 (Linux01)(ORCL): 

log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';  >> This is to tell oracle that what all instances are part of this config

*.db_file_name_convert='/ORCLSTB1/','/ORCL/','/ORCLSTB2/','/ORCL/'        -- > add both servers so oracle knows where to create file. 

*.db_name='ORCL'  ### same across all Databases 

*.db_unique_name='ORCL'  ### Unique across each Database 

FAL_SERVER=ORCLSTB1, ORCLSTB2-- > add both servers so oracle knows where to get the archive files from incase of switchover. 

FAL_CLIENT=ORCLThis is always the Current DB server typically standby DB. This is ignored when the DB is in Primary mode 

PFILE DB_* PARAMETERS on DB SERVER2 (Linux02)(ORCLSTB1): 

log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';
*.db_file_name_convert='/ORCL/','/ORCLSTB1/','/ORCLSTB2/','/ORCLSTB1/' 

*.db_name='ORCL'### same across all Databases 

*.db_unique_name='ORCLSTB1'                    ### Unique across each Database 

*.FAL_CLIENT=STANDBY_SERVER 

*.FAL_SERVER=PRIMARY_SERVERS 

PFILE DB_* PARAMETERS on DB SERVER3 (Linux03)(ORCLSTB2): 

log_archive_config='dg_config=(ORCL,ORCLSTB1,ORCLSTB2)';
*.db_file_name_convert='/ORCLSTB1/','/ORCLSTB2/','/ORCL/','/ORCLSTB2/' 

*.db_name='ORCL'### same across all Databases 

*.db_unique_name='ORCLSTB2'                 ### Unique across each Database 

*.FAL_CLIENT=STANDBY_SERVER 

*.FAL_SERVER=PRIMARY_SERVERS