DR Setup Configuration: ( ORA-WEEK on 19th Apr )

ORA-WEEK:
=========

19th APR:
---------

DR Setup Configuration:
-----------------------

Imp Pts 2 Remember:
===================

On Primary:
-----------
Enable Force Logging
You should enable Force logging in primary database else if some transaction which doesn’t generate redo log can corrupt your standby database.
(Careful in OLTP transactions or long running requests in Apps)
SQL> ALTER DATABASE FORCE LOGGING;

Create the  standby control file:
---------------------------------
go to mount state and then

SQL> alter database create standby controlfile as ‘/stdbyctl.dbf’

init.ora para's to set:
-----------------------
LOG_ARCHIVE_DEST_1 =’LOCATION=/u01/oracle/data/arch’
LOG_ARCHIVE_DEST_2 =’SERVICE=PROD_remote1.domain.com LGWR ASYNC REOPEN=60'
fal_client =
server_client=

Dataguard broker tool:
----------------------
These primary & standby database can be monitored by command line (sql) as well from GUI (Graphical User Interface) Tool called as Dataguard broker.

2 Services will be running to keep standby database in synch with primary database:
----------------------------------------------------------------------------------
1. redo transport service - transfer(Pull/Push) redo logs from primary to standby database &
2. Log apply service - applies that redo logs to standby database.

Switchover & Failover:
----------------------
These are basically two kind of roles in dataguard Failover & Switchover;
Switchover:
Primary database becomes standby database & one of (If there are more than one standby) standby database becomes primary database for ex. during server maintenance.

Failover:
Failover is used in scenarion in which your primary database is not available and you want to convert role of one of standby database to primary database for ex. during primary database failure.

Data Protection Mode : 3 Modes ( Maximum Protection Mode , Maximum Availability Mode & Maximum Performance Mode )


Maximum Protection Mode:
------------------------

In maximum protection mode as name suggest no data loss will occur if primary database fails. This is achieved by oracle by ensuring that redo data must be written to both local online redo log location & standby redo log location before transaction commits. This standby redo log will ensure full data protection. For full protection mode atleast one standby database should have standby redo log and LGWR, SYNC, and AFFIRM attribute should be used with LOG_ARCHIVE_DEST_n parameter. (I am going to discuss about these parameters in next post)
Here your primary database will shutdown if it is unable to write redo records to atleast one standby location.


Maximum Availability Mode:
--------------------------

This is similar to Maximum protection mode except that it will not shutdown primary database if primary database is not able to write standby redo logs to atleast one standby location but in that case Maximum Availability will act in Maximum Performance Mode until fault is corrected and all gaps in redo logs are resolved. Once all gaps are resolved primary database will automatically goes into Maximum Availability Mode.


Maximum Performance Mode:
-------------------------

This is default mode in which redo stream is written asynchronously with respect to the commitment of the transactions that create the redo data. You can use LGWR and ASYNC attribute or ARCH attribute in LOG_ARCHIVE_DEST_n

You can check your database mode as

SQL> select PROTECTION_LEVEL from v$database;
PROTECTION_LEVEL
—————————-
MAXIMUM PERFORMANCE

More and More in

http://onlineappsdba.com/index.php/2006/11/28/configure-oracle-dataguard/