Oracle 11g part 3

Oracle 11g part 3

Continuing with the last uncovered topics from the last document:

· Network-enabled database duplication without backups

You can use the DUPLICATE command to create a duplicate database or physical standby database over the network without a need for pre-existing database backups. This form of duplication is called active database duplication.

· Improved integration with Data Guard

You can now set persistent RMAN configurations for a primary or physical standby database when RMAN is not connected as TARGET to the database. RMAN works seamlessly on all databases in the Data Guard environment, enabling you to use backups made on one database for restore and recovery on another database. The same recovery catalog can manage metadata for all primary and standby databases.

· Block change tracking support for standby databases

You can enable block change tracking on a physical standby database. When you back up the standby database, RMAN can use the block change tracking file to quickly identify the blocks that changed since the last incremental backup.

· Integration with VSS-enabled applications

The Oracle VSS writer is integrated with applications that use the Volume Shadow Copy Service (VSS) infrastructure on Windows. You can use VSS-enabled software and storage systems to back up and restore an Oracle database. A key benefit is the ability to make a shadow copy of an open database.

· Lost write detection

You can enable the DB_LOST_WRITE_PROTECT initialization parameter to detect a lost write during managed recovery of a standby database or media recovery of a primary database. Lost write detection is disabled by default.

· Oracle Flashback Transaction Backout

You can reverse a transaction. Oracle Database determines the dependencies between transactions and in effect creates a compensating transaction that reverses the unwanted changes. The database rewinds to a state as if the transaction, and any transactions that could be dependent on it, never occurred.

· Flashback data archive

A flashback data archive enables the database to automatically track and store all transactional changes to a table for the duration of its lifetime. Thus, you do not need to build this functionality into database applications.

A flashback data archive is especially useful for compliance, audit reports, data analysis, and DSS (Decision Support Systems). You can use some of the logical flashback features with a flashback data archive to access data from far in the past.

Network-enabled database duplication without backups.

Before Oracle 11g when we want to duplicate a database using RMAN we had only the backup-based duplication, that means we should send our backup to the destination before start the duplicate session, now with Oracle 11g we can perform the Active Database Duplication, that basically means Oracle will create all duplicated control files, redo logs and datafiles automatically on the destination side, and it will use an auxiliary channel to transfer the data, also you can duplicate the whole database or just a subset of it.

To duplicate a database in a host with the same file system structure using Active Database Duplication:

1 – Create an auxiliary instance on the destination host, basically you can copy your initfile from the target and just change the instance name to aux for example.

Create the password file:

Orapwd file=orapwaux password=oracle

After that start the instance on the destination side.

We need to have the password file because a session will be created using the SYS account from the source to the destination database.

2 – Create the same directory structure on the destination side, in my case:

/oracle/oradata/test

3 – Configure the tns and listener for both servers.

4 – Now connect on the target database as described and also in the auxiliary database, where you are going to duplicate it.

rman

Recovery Manager: Release 11.1.0.6.0 - Production on Thu Aug 30 11:49:36 2007

RMAN> connect target sys/oracle@test

connected to target database: TEST (DBID=1928403553)

RMAN> connect auxiliary sys/oracle@aux

connected to auxiliary database: TEST (not mounted)

5 – Executing the duplicate command, you will see that it show all the commands that it automatically executes:

RMAN> DUPLICATE TARGET DATABASE

2> TO AUX

3> FROM ACTIVE DATABASE

4> SPFILE

5> NOFILENAMECHECK;

Starting Duplicate Db at 30-AUG-07

using target database control file instead of recovery catalog

allocated channel: ORA_AUX_DISK_1

channel ORA_AUX_DISK_1: SID=152 device type=DISK

contents of Memory Script:

{

backup as copy reuse

file '/oracle/11.1/dbs/spfiletest.ora' auxiliary format

'/oracle/11.1/dbs/spfileaux.ora' ;

sql clone "alter system set spfile= ''/oracle/11.1/dbs/spfileaux.ora''";

}

executing Memory Script

Starting backup at 30-AUG-07

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=142 device type=DISK

Finished backup at 30-AUG-07

sql statement: alter system set spfile= ''/oracle/11.1/dbs/spfileaux.ora''

contents of Memory Script:

{

sql clone "alter system set db_name =

''AUX'' comment=

''duplicate'' scope=spfile";

sql clone "alter system set db_unique_name =

''AUX'' comment=

''duplicate'' scope=spfile";

shutdown clone immediate;

startup clone nomount ;

}

executing Memory Script

sql statement: alter system set db_name = ''AUX'' comment= ''duplicate'' scope=spfile

sql statement: alter system set db_unique_name = ''AUX'' comment= ''duplicate'' scope=spfile

Oracle instance shut down

connected to auxiliary database (not started)

Oracle instance started

Total System Global Area 732352512 bytes

Fixed Size 1302428 bytes

Variable Size 675283044 bytes

Database Buffers 50331648 bytes

Redo Buffers 5435392 bytes

contents of Memory Script:

{

set newname for datafile 1 to

"/oracle/oradata/test/system01.dbf";

set newname for datafile 2 to

"/oracle/oradata/test/sysaux01.dbf";

set newname for datafile 3 to

"/oracle/oradata/test/sqlmag01.dbf";

set newname for datafile 4 to

"/oracle/oradata/test/users01.dbf";

set newname for datafile 5 to

"/oracle/oradata/test/test_block01.dbf";

set newname for datafile 6 to

"/oracle/oradata/test/rman_catalog01.dbf";

set newname for datafile 7 to

"/oracle/oradata/test/undotbs201.dbf";

backup as copy reuse

datafile 1 auxiliary format

"/oracle/oradata/test/system01.dbf" datafile

2 auxiliary format

"/oracle/oradata/test/sysaux01.dbf" datafile

3 auxiliary format

"/oracle/oradata/test/sqlmag01.dbf" datafile

4 auxiliary format

"/oracle/oradata/test/users01.dbf" datafile

5 auxiliary format

"/oracle/oradata/test/test_block01.dbf" datafile

6 auxiliary format

"/oracle/oradata/test/rman_catalog01.dbf" datafile

7 auxiliary format

"/oracle/oradata/test/undotbs201.dbf" ;

sql 'alter system archive log current';

}

executing Memory Script

executing command: SET NEWNAME

Starting backup at 30-AUG-07

using channel ORA_DISK_1