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Dataguard

Start up the apply on a physical standby

startup nomount alter database mount standby database; alter database recover managed standby database disconnect;

Stop the apply on a physical standby

alter database recover managed standby database cancel;

Register a missing logfile

alter database register physical logfile '<fullpath/filename>';

Show apply activity on the standby

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shows something like this

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See Dataguard error log messages

If data guard is not functioning correctly, check the errors in this log.

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and

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Check which logs are missing

Assuming dest_2 is the standby select local.thread# , local.sequence# from

      (select thread#
      ,       sequence# 
      from    v$archived_log 
      where dest_id=1) local

where local.sequence# not in

      (select sequence#
      from v$archived_log
      where dest_id=2 and 
      thread# = local.thread#);

Stop/Start log file shipping

On the primary alter system set log_archive_dest_state_2 = 'defer'; alter system set log_archive_dest_state_2 = 'enable';

Start FAL tracing on the primary

alter system set LOG_ARCHIVE_TRACE = 128;

Stop the DataGuard broker

alter system set dg_broker_start=false;

Are we a standby?

select database_role from v$database;

Show various details on health of standby database

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See how up-to-date a standby is

On the primary

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On the standby

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or

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See how up-to-date a standby is (another version)

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Show info on all log destinations

On the primary

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Display log destinations options

On the standby

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Show any standby logs

set lines 100 set pages 999 col member format a70 select st.group# , st.sequence# , ceil(st.bytes/1048576) mb , lf.member from v$standby_log st , v$logfile lf where 1=1 and st.group# = lf.group#

Dataguard broker (dgmgrl) setup for management of physical standby databases

Assuming primary and standby already exist and have standby redologs setup, force logging etc… Example: server1 - db_primary, server2 - db_standby

Preparation

On both systems…

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Create a configuration

From server1

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Configuration created, add the physical standby to it

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Configuration complete, enable it

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Show configuration

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Show individual database information

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Switchover primary to standby and vice versa

From server1

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Switch back to the original situation

From server2

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Failover

The difference between switchover and failover is that you control a switchover, a failover happens bacause the primary db is no longer available From server2

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Backup this database immediately as it is now the only database and has no standby. This can be done with RMAN while it is running. If flashback was not enabled, the old primary is now useless and will need to be recreated as a standby. If, however flashback was enabled, we can use this to restart the old primary as a standby. From server1

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If flashback was not enabled, recreate old primary as a standby something like this

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Dataguard broker managed standby (dgmgrl) not applying logs after restart

After restarting the Primary and Standby databases manually, the redo logs were not being applied on the standby. The command used to start the standby database was:

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It seems this is not good enough, we see a problem in the broker configuration… (0) OTMPRODS oracle@ravotm14:/home/oracle] dgmgrl DGMGRL for Linux: Version 11.2.0.4.0 - 64bit Production

Welcome to DGMGRL, type “help” for information. DGMGRL> connect sys/@otmprod Connected. DGMGRL> show configuration

Configuration - dg_otmprod

Protection Mode: MaxPerformance

 Databases:
   otmprod  - Primary database
   otmprods - **Physical standby database (disabled)**

Fast-Start Failover: DISABLED

Configuration Status: SUCCESS

DGMGRL> We need to re-enable the Standby database in the broker configuration DGMGRL> enable database OTMPRODS; Enabled. DGMGRL> show configuration