DATA GUARD BROKER CONFIGURATION AND OPERATIONS IN 11g.pdf
May 4, 2017 | Author: G.R.THIYAGU ; Oracle DBA | Category: N/A
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DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
A DATA GUARD BROKER
In this article I present about Data Guard Broker and also steps to configure Data Guard Broker. The Data Guard Broker logically groups Primary and all Standby databases in a DATA GUARD setup into a broker configuration to manage and monitor them. All operations can be performed either through OEM (GUI) or the broker’s Command line Interface (DGMGRL). The Broker Consists of Three Major Parts Broker Configuration files Background Processes on each node Command line interface known as DGMGRL CONFIGURATION FILES
By default, the Data Guard Broker has two copies of configuration files located at $ORACLE_HOME/dbs with file name of dr1_db_unique_name.dat and dr2_db_unique_name.dat
SYS> SHOW PARAMETERS DG_BROKER_CONFIG; NAME
TYPE
VALUE
-------------------------- ---------- ------------------------------------------------------dg_broker_config_file1
string
/u01/app/oracle/product/11.2.0/db_home1/dbs/dr1crms.dat
dg_broker_config_file2
string
/u01/app/oracle/product/11.2.0/db_home1/dbs/dr2crms.dat
When the broker is started for the first time, the configuration files are automatically created and names using default path name and filename. You must set these parameters on the primary (production) database as well as on any standby databases. If you wish to override you can using alter system set command? In My Opinion, It’s a bad practice to keep both files in same place especially on the Primary database. SYS> alter system set dg_broker_config_file1='/preferred location/'
...
SYS> alter system set dg_broker_config_file2='/preferred location/'
...
You can only be set or changed when the Data Guard broker is not running (DG_BROKER_START=FALSE). Its recommend to place these files on different disks so single disk failure does NOT affect your broker configuration. The Primary has the master copies of the configuration files, because the broker is Primary-Centric. All changes to these files are done by the primary, even if you are on the standby server the configuration changes will be passed to the primary via NSV-DRC processes and the DMON process will make the change which is then propagated back to the standby databases. If the primary has a problem then each standby database has a copy, when a failover occurs the Standby that becomes the primary then become the master of those configuration files.
DMON PROCESS
DMON stands for Data Guard Monitor Process specific to Data Guard Broker. If Data Guard Broker is enabled, Oracle uses Data Guard Broker Monitor (DMON) background process to manage and monitor the primary and standby databases as a unified configuration.
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This Process runs for every database instance that is managed by broker and gets enabled when you set DG_BROKER_START=TRUE. By default the value of DG_BROKER_START=FALSE. DMON is the server side component that interacts with local database and the DMON process of the other database to perform requested function. This is responsible for monitoring health of the broker configuration and maintains consistent description of configuration files. DATABASES WITH BROKER (DMON) PROCESSES
BACKGROUND PROCESSES
DATA GUARD BROKER PROCESSES
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In Data Guard Broker configuration, DMON Process on the Primary database that is the owner of the configuration, all Commands to modify any configuration comes only from the Primary (though you may connect any database using DGMGRL Client), all Standby databases receive all configuration changes via the Primary. BROKER RESOURCE MANAGER (RSM)
When DMON needs to execute some SQL statement, (if SQL is for Primary with the help of RFS process, it will execute it directly. Suppose SQL is for the standby database, the RSM asks the NSV process to send it to the standby database. The configuration commands executed by the broker during the database startup or may be required to be run during Data Guard setup.
DATA GUARD NET SERVER – (NSVn)
NSV processes are responsible for making connection with the remote database. DMON or RSM process may ask NSV process to connect to other node for any work request. DMON may need to send some communication to the other node and RSM may have to get some data through SQL from other node. Each NSV Process will have DRC process on the Standby database, which performs the actual work on behalf of the NSV process, the DRS process on the standby will return the status back to NSV Process on the Primary. The DMON Process of the Primary database tries to communicate with each Standby via NSV-DRC pair to establish communication and configuration info so that the standby can start and apply services. DRCn
NSV Processes contact DRC process running on the other node to establish the connection, so DRC acts like a receiver on the other node.
INTER NODE SERVERS (INSVs)
When using RAC environment, there are some set of processes called the internode servers (INSV). Which maintain a connection between the nodes in the cluster to ensure that the broker on each node knows the state of the cluster.
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COMMAND LINE INTERFACE - DGMGRL
The third part of broker setup is the interface through which users will interact with broker. Let’s start to configure DGMGRL. DISASTER RECOVERY ENVIRONMENT
OPERATING SYSTEM
: RHEL
DATABASE SOFTWARE : 11.2.0.1 PRIMARY DB_NAME
: CRMS
STANDBY DB_NAME
: CRMS
PRIMARY DATABASE UNIQUE NAME : CRMS STANDBY DATABASE UNIQUE NAME : STBYCRMS PRIMARY SERVER
192.168.1.130
SERVER1.ORACLE.COM
SERVER1
PRODUCTION DATABASE
STANDBY SERVER
192.168.1.131
SERVER2.ORACLE.COM
SERVER2
STANDBY DATABASE
CONFIGURING DATA GUARD BROKER
TO SET DG_BROKER_START=TRUE on both databases. The Primary database to be open. The Standby database to have been mounted.
VERIFY DG_BROKER_START PARAMETER
# ON PRIMARY DATABASE AND STANDBY DATABASE SYS> show parameter DG_BROKER_START; NAME
TYPE
VALUE
------------------------------------ ----------- -----------------------------dg_broker_start
boolean
FALSE
SET DG_BROKER_START TO TRUE
# ON PRIMARY DATABASE SYS> alter system set DG_BROKER_START=TRUE scope=both; System altered. # ON STANDBY DATABASE SYS> alter system set DG_BROKER_START=TRUE scope=both; System altered. # ON PRIMARY DATABASE SYS> show parameter db_domain; NAME
TYPE
VALUE
------------------------------------ ----------- --------------------db_domain
string
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# ON STANDBY DATABASE SYS> show parameter db_domain; NAME
TYPE
VALUE
------------------------------------ ----------- ----------------------db_domain
string
The value of db_domain is null. GLOBAL_DBNAME should be set db_unique_name_DGMGRL, so the value of GLOBAL_DBNAME = crms_DGMGRL for Primary database and for Standby GLOBAL_DBNAME = stbycrms_DGMGRL.
# ON PRIMARY SERVER – listener.ora file contents # listener.ora Network Configuration File: /u01/app/oracle/product/11.2.0/db_home1/network/admin/listener.ora # Generated by Oracle configuration tools. LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.130)(PORT = 1521)) ) ) ADR_BASE_LISTENER = /u01/app/oracle SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = crms) (GLOBAL_DBNAME = crms_DGMGRL) (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_home1) ) (SID_DESC = (SID_NAME = crms) (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_home1) ) )
# ON STANDBY SERVER – listener.ora file CONTENTS # listener.ora Network Configuration File: /u01/app/oracle/product/11.2.0/db_home1/network/admin/listener.ora # Generated by Oracle configuration tools. LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.131)(PORT = 1521)) ) )
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ADR_BASE_LISTENER = /u02/app/oracle SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = stbycrms) (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_home1) ) (SID_DESC = (SID_NAME = stbycrms) (GLOBAL_DBNAME = stbycrms_DGMGRL) (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_home1) ) ) Now check listener status on both servers. BROKER CONFIGURATION ON PRIMARY SERVER
$ dgmgrl DGMGRL for Linux: Version 11.2.0.1.0 - Production Copyright (c) 2000, 2009, Oracle. All rights reserved. Welcome to DGMGRL, type "help" for information. DGMGRL> connect sys/passwd@CRMSDB Connected. # ON PRIMARY DATABASE DGMGRL> create configuration as primary database is connect identifier is ; DGMGRL> create configuration dgcrms as primary database is crms connect identifier is CRMSDB; Configuration "dgcrms" created with primary database "crms" DGMGRL> show configuration; Configuration - dgcrms Protection Mode : MaxPerformance Databases : crms - Primary database Fast-Start Failover : DISABLED Configuration Status : DISABLED
# ADDING THE PHYSICAL STANDBY DATABASE DGMGRL> add database as connect identifier is maintained as physical; DGMGRL> add database stbycrms as connect identifier is STBY_CRMSDB maintained as physical; Database "stbycrms" added
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DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases:
crms
stbycrms
- Primary database - Physical standby database
Fast-Start Failover: DISABLED Configuration Status: DISABLED # CONFIGURATION NEEDS TO BE ENABLED DGMGRL> enable configuration; Enabled. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS DGMGRL> show database verbose crms; Database - crms Role:
PRIMARY
Intended State:
TRANSPORT-ON
Instance(s): crms Properties: DGConnectIdentifier
= 'crmsdb'
ObserverConnectIdentifier
= ''
LogXptMode
= 'ASYNC'
DelayMins
= '0'
Binding
= 'optional'
MaxFailure
= '0'
MaxConnections
= '1'
ReopenSecs
= '300'
NetTimeout
= '30'
RedoCompression
= 'DISABLE'
LogShipping
= 'ON'
PreferredApplyInstance
= ''
ApplyInstanceTimeout
= '0'
ApplyParallel
= 'AUTO'
StandbyFileManagement
= 'AUTO'
ArchiveLagTarget
= '0'
LogArchiveMaxProcesses
= '4'
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LogArchiveMinSucceedDest
= '1'
DbFileNameConvert
= '...
LogFileNameConvert
= '...
FastStartFailoverTarget
= ''
StatusReport
= '(monitor)'
InconsistentProperties
= '(monitor)'
InconsistentLogXptProps
= '(monitor)'
SendQEntries
= '(monitor)'
LogXptStatus
= '(monitor)'
RecvQEntries
= '(monitor)'
HostName
= 'SERVER1.ORACLE.COM'
SidName
= 'crms'
StaticConnectIdentifier
=
'(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=SERVER1.ORACLE.COM)(PORT=1521))(CONNECT_DATA= (SERVICE_NAME=crms_DGMGRL)(INSTANCE_NAME=crms)(SERVER=DEDICATED)))' StandbyArchiveLocation
= 'USE_DB_RECOVERY_FILE_DEST'
AlternateLocation
= ''
LogArchiveTrace
= '0'
LogArchiveFormat
= '%t_%s_%r.dbf'
TopWaitEvents
= '(monitor)'
Database Status:
SUCCESS
DGMGRL> show database verbose stbycrms; Database - stbycrms Role:
PHYSICAL STANDBY
Intended State:
APPLY-ON
Transport Lag:
0 seconds
Apply Lag:
0 seconds
Real Time Query: ON Instance(s): stbycrms Properties: DGConnectIdentifier
= 'stby_crmsdb'
ObserverConnectIdentifier
= ''
LogXptMode
= 'ASYNC'
DelayMins
= '0'
Binding
= 'OPTIONAL'
MaxFailure
= '0'
MaxConnections
= '1'
ReopenSecs
= '300'
NetTimeout
= '30'
RedoCompression
= 'DISABLE'
LogShipping
= 'ON'
PreferredApplyInstance
= ''
ApplyInstanceTimeout
= '0'
ApplyParallel
= 'AUTO'
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StandbyFileManagement
= 'AUTO'
ArchiveLagTarget
= '0'
LogArchiveMaxProcesses
= '4'
LogArchiveMinSucceedDest
= '1'
DbFileNameConvert
= '...
LogFileNameConvert
= '...
FastStartFailoverTarget
= ''
StatusReport
= '(monitor)'
InconsistentProperties
= '(monitor)'
InconsistentLogXptProps
= '(monitor)'
SendQEntries
= '(monitor)'
LogXptStatus
= '(monitor)'
RecvQEntries
= '(monitor)'
HostName
= 'SERVER2.ORACLE.COM'
SidName
= 'stbycrms'
StaticConnectIdentifier
=
'(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=SERVER2.ORACLE.COM)(PORT=1521))(CONNECT_DATA= (SERVICE_NAME=stbycrms_DGMGRL)(INSTANCE_NAME=stbycrms)(SERVER=DEDICATED)))' StandbyArchiveLocation
= 'USE_DB_RECOVERY_FILE_DEST'
AlternateLocation
= ''
LogArchiveTrace
= '0'
LogArchiveFormat
= '%t_%s_%r.dbf'
TopWaitEvents
= '(monitor)'
Database Status: SUCCESS DGMGRL> help add
Adds a standby database to the broker configuration
connect
Connects to an Oracle database instance
convert
Converts a database from one type to another
create
Creates a broker configuration
disable
Disables a configuration, a database, or fast-start failover
edit
Edits a configuration, database, or instance
enable
Enables a configuration, a database, or fast-start failover
exit
Exits the program
failover
Changes a standby database to be the primary database
help
Displays description and syntax for a command
quit
Exits the program
reinstate
Changes a database marked for reinstatement into a viable standby
rem
Comment to be ignored by DGMGRL
remove
Removes a configuration, database, or instance
show
Displays information about a configuration, database, or instance
shutdown
Shuts down a currently running Oracle database instance
start
Starts the fast-start failover observer
startup
Starts an Oracle database instance
stop
Stops the fast-start failover observer
switchover
Switches roles between a primary and standby database
Use "help " to see syntax for individual commands
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EQUIVALENT BROKER COMMNADS TO ALTER SYSTEM
DGMGRL> SHOW DATABASE 'crms' 'LogArchiveMaxProcesses'; LogArchiveMaxProcesses = '4' SYS> alter system set log_archive_max_processes=8 scope=spfile; DGMGRL> EDIT DATABASE 'crms' SET PROPERTY 'LogArchiveMaxProcesses'=8; Property "LogArchiveMaxProcesses" updated DGMGRL> SHOW DATABASE 'crms' 'LogArchiveMaxProcesses'; LogArchiveMaxProcesses = '8' SYS> alter database recover managed standby database cancel; DGMGRL> edit database 'stbycrms' set state='LOG-APPLY-OFF'; SYS> alter database recover managed standby database disconnect from session; DGMGRL> edit database 'stbycrms' set state='ONLINE'; SYS> alter database set log_archive_dest_2='defer' scope=both; DGMGRL> edit database 'stbycrms' set property 'LogShipping'='OFF'; SYS> alter database set log_archive_dest_2='enable' scope=both; DGMGRL> edit database 'stbycrms' set property 'LogShipping'='ON';
PERFORM A SWITCHOVER TEST
DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status:SUCCESS
DGMGRL> switchover to stbycrms; Performing switchover NOW, please wait... New primary database "stbycrms" is opening... Operation requires shutdown of instance "crms" on database "crms" Shutting down instance "crms"... ORA-01109: database not open Database dismounted. ORACLE instance shut down. Operation requires startup of instance "crms" on database "crms" Starting instance "crms"... ORACLE instance started. Database mounted. Switchover succeeded, new primary is "stbycrms"
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DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: stbycrms - Primary database crms
- Physical standby database
Fast-Start Failover: DISABLED Configuration Status: SUCCESS # The FORMER STANDBY DATABASE IS NOW THE NEW PRIMARY DATABASE SYS> select name, db_unique_name, database_role, open_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
OPEN_MODE
--------- ------------------------------ ---------------- -------------------CRMS
stbycrms
PRIMARY
READ WRITE
# The FORMER PRIMARY DATABASE IS NOW THE NEW PHYSICAL STANDBY SYS> select database_role, db_unique_name, protection_level, open_mode from v$database; DATABASE_ROLE
DB_UNIQUE_NAME
PROTECTION_LEVEL
OPEN_MODE
----------------- -----------------
--------------------- ----------
PHYSICAL STANDBY
MAXIMUM PERFORMANCE
crms
MOUNTED
SYS> select DEST_ID,DEST_NAME,STATUS,TYPE,SRL,RECOVERY_MODE from v$archive_dest_status where dest_id=1; DEST_ID
DEST_NAME
STATUS
--------- ------------------1
TYPE
SRL
-------- ------- -----
LOG_ARCHIVE_DEST_1
VALID
LOCAL
NO
RECOVERY_MODE -----------------------MANAGED REAL TIME APPLY
POINTS TO NOTE The broker automatically enables real-time-apply on standby databases. When Redo Apply in real time, the redo data is recovered directly from the standby redo log files as they are being filled. The standby database does not have to wait for the log files to be archived before applying redo data from the archived redo log files. This minimizes the transactional lag between the primary and the standby. Reference doc here
IS STANDBY IN SYNC WITH PRIMARY ?
# ON THE PRIMARY DATABASE SYS> select thread#, max(sequence#) from v$archived_log group by thread#; THREAD#
MAX(SEQUENCE#)
---------- -------------1
14722
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# ON STANDBY DATABASE SYS> select thread#, max(sequence#) from v$archived_log where applied='YES' group by thread#; THREAD#
MAX(SEQUENCE#)
---------- -------------1
14722
QUERYING STANDBY REDO LOG FILES ON STANDBY SITE
# ON STANDBY DATABASE SYS> select group#, sequence#, bytes, used,status from v$standby_log; GROUP#
SEQUENCE#
BYTES
USED STATUS
---------- ---------- ---------- ---------- ---------4
14723
52428800
1263104 ACTIVE
5
0
52428800
512 UNASSIGNED
6
0
52428800
512 UNASSIGNED
7
0
52428800
512 UNASSIGNED
SHOW THE CONFIGURATION
DGMGRL> show database crms; Database - crms Role:
PHYSICAL STANDBY
Intended State : APPLY-ON Transport Lag
: 0 seconds
Apply Lag
: 0 seconds
Real Time Query: OFF Instance(s)
: crms
Database Status
: SUCCESS
DGMGRL> show database stbycrms; Database - stbycrms Role
:
PRIMARY
Intended State:
TRANSPORT-ON
Instance(s)
stbycrms
:
Database Status :
SUCCESS
SWITCHOVER TO THE FORMER PRIMARY DATABASE :
DGMGRL> switchover to crms; Performing switchover NOW, please wait... New primary database "crms" is opening... Operation requires shutdown of instance "stbycrms" on database "stbycrms" Shutting down instance "stbycrms"... ORA-01109: database not open
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Database dismounted. ORACLE instance shut down. Operation requires startup of instance "stbycrms" on database "stbycrms" Starting instance "stbycrms"... ORACLE instance started. Database mounted. Switchover succeeded, new primary is "crms" DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover : DISABLED Configuration Status: SUCCESS
# ON PRIMARY DATABASE SYS> select name, db_unique_name, database_role, open_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
OPEN_MODE
--------- ------------------------------ ---------------- -------------------CRMS
crms
PRIMARY
READ WRITE
# ON STANDBY DATABASE SYS> select name, db_unique_name, database_role, open_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
OPEN_MODE
--------- ------------------------------ ---------------- -------------------CRMS
stbycrms
PHYSICAL STANDBY
MOUNTED
SYS> select DEST_ID, DEST_NAME, STATUS, TYPE, SRL, RECOVERY_MODE from v$archive_dest_status where dest_id=1; DEST_ID -------1
DEST_NAME
STATUS
------------------ ------LOG_ARCHIVE_DEST_1
VALID
TYPE
SRL
------- ---LOCAL
NO
RECOVERY_MODE -------------------------MANAGED REAL TIME APPLY
DGMGRL> show database crms Database - crms Role:
PRIMARY
Intended State:
TRANSPORT-ON
Instance(s):
crms
Database Status: SUCCESS
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DGMGRL> show database stbycrms; Database - stbycrms Role:
PHYSICAL STANDBY
Intended State
:
APPLY-ON
Transport Lag
:
0 seconds
Apply Lag
:
0
Real Time Query :
ON
Instance(s)
stbycrms
:
Database Status: SUCCESS
CHANGE DATAGUARD PROTECTION MODE
We can change Data Guard Protection mode using Data Guard command line interface (DGMGRL). Already Physical Standby database is configured as MAXIMUM PERFORMANCE. This scenario sets Protection mode of the configuration would be MAXIMUM AVALIABILITY. Configure Standby Redolog files. Set database property LogXptMode to SYNC Maximum Availability Protection mode requires standby redolog files on the standby database. In order to change from MAXIMUM PERFORMANCE to MAXIMUM AVAILABILITY the Log Transport Mode LogXptMode must be set to SYNC. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS DGMGRL> EDIT DATABASE 'stbycrms' SET PROPERTY 'LOGXPTMODE'='SYNC'; Property "LogXptMode" updated The broker will not allow this command to succeed unless the standby database is configured with standby redo log files in the configuration. Now you can change the protection mode to MAXIMUM AVAILABILITY. The protection mode is changed using the EDIT CONFIGURATION SET PROTECTION MODE AS command. DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY; Succeeded. Suppose configuration is disabled when you enter above command, protection mode is not applied until you enable the configuration using ENABLE CONFIGURATION command.
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# VERIFY PROTECTION MODE USING SHOW CONFIGURATION COMMAND DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxAvailability Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS
CHANGE FROM MAXIMUM AVAILABILITY TO MAX PROTECTION
DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXPROTECTION; Succeeded. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxProtection Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS
CHANGE FROM MAXIMUM PROTECTION TO MAX PERFORMANCE
DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXPERFORMANCE; Succeeded. DGMGRL> EDIT DATABASE STBYCRMS SET PROPERTY LOGXPTMODE='ASYNC'; Property "logxptmode" updated DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS As we know changing the protection mode is very simple using DGMGRL. But anyhow a point to note that when you change protection mode from MAX PERFORMANCE to MAX PROTECTION, ensure first process would be change to max availability and then to max protection. Otherwise Primary will be taken down. Let’s see
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CHANGE FROM MAXIMUM PERFORMANCE TO MAXIMUM PROTECTION
Now you can set the protection mode to Maximum Protection from Maximum Performance. Changing directly to Maximum Protection mode requires the restart of the primary database. DGMGRL> EDIT DATABASE stbycrms SET PROPERTY LOGXPTMODE=SYNC; Property "logxptmode" updated DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXPROTECTION; Operation requires shutdown of instance "crms" on database "crms" Shutting down instance "crms"... Database closed. Database dismounted. ORACLE instance shut down. Operation requires startup of instance "crms" on database "crms" Starting instance "crms"... ORACLE instance started. Database mounted. Database opened. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxProtection Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS # ON PRIMARY DATABASE SYS> show parameter log_archive_dest_2; NAME
TYPE
VALUE
-------------------------- ----------- -----------------------------------------------------log_archive_dest_2
string
service="stby_crmsdb", LGWR SYNC AFFIRM DELAY=0 optional compression=disable max_failure=0 max_connections=1 reopen=300 db_unique_name="stbycrms" net_timeout=30, valid_for=(all_logfiles, primary_role)
# ON STANDBY DATABASE SYS> show parameter log_archive_dest_2; NAME
TYPE
VALUE
-------------------------- ----------- -----------------------------------------------------log_archive_dest_2
string
service="stby_crmsdb", LGWR ASYNC AFFIRM valid_for=(all_logfiles, primary_role) db_unique_name="stbycrms"
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LOGXPTMODE =SYNC/ASYNC
ASYNC should be used when LGWR is used to transfer logs in MAX PERFORMANCE mode. This is default. SYNC is for MAX AVAILABILITY or MAX PROTECTION mode. Before you perform switchover process, you need to change database property LogXptMode of the Primary database also it is taken care during a transition. Already we have changed LogXptMode=SYNC in primary database to send redo data for standby database. But still we maintain LogXptMode=ASYNC in standby database. Before switch over process we need to set LogXptMode=SYNC at both side, If Protection mode is MAX AVAILABILITY or MAX PROTECTION. If you ignore you would get following ORA ERROR. Error: ORA-16627: operation disallowed since no standby databases would remain to support protection mode Failed.
DGMGRL> switchover to stbycrms; .. ... Switchover succeeded, new primary is "stbycrms" # EXECUTE FOLLOWING SQL STATEMENT AT BOTH SIDE SYS> select name, db_unique_name, database_role, protection_mode from v$database; ... I reset Protection Mode as MAXIMUM PERFORMANCE and LogXptMode=ASYNC at both side.
CONVERY PHYSICAL STANDBY TO SNAPSHOT STANDBY
Steps to convert a Physical Standby database to Snapshot Standby database using Data Guard broker command line interface DGMGRL. Redo data will continue to be received by the database while it is operating as a snapshot standby database but redo will not be applied until the Snapshot Standby is converted back into Physical Standby database. The flashback feature is required to create a snapshot standby database. If flashback database is disabled, it is enabled automatically during conversion to a snapshot standby database.
# VERIFY DATABASE DETAILS DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerfromance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS
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DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
# CONVERT A PHYSICAL STANDBY TO A SNAPSHOT DATABASE DGMGRL> convert database stbycrms to snapshot standby; Converting database "crms" to a Snapshot Standby database, please wait... Database "stbycrms" converted successfully $ tail –f alert_stbycrms.log .. ... alter database convert to snapshot standby Starting background process RVWR Tue Nov 16 04:22:15 2015 RVWR started with pid=20, OS id=25510 Allocated 15937428 bytes in shared pool for flashback generation buffer Created guaranteed restore point SNAPSHOT_STANDBY_REQUIRED_11/16/2015 04:22:15 DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Snapshot standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS
# CHECH STANDBY DATABASE SYS> select name, db_unique_name, database_role, protection_mode
from v$database;
NAME
DB_UNIQU
DATABASE_ROLE
PROTECTION_MODE
---------
-----------
-------------------- --------------------
CRMS
stbycrms
SNAPSHOT STANDBY
MAXIMUM PERFORMANCE
SYS> select open_mode, flashback_on from v$database; OPEN_MODE
FLASHBACK_ON
-------------------- -----------------READ WRITE
RESTORE POINT ONLY
# CHECK ARCHIVE LOG DETALS ON PRIMARY DATBASE SYS> archive log list; Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
14943
Next log sequence to archive
14945
Current log sequence
14945
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
SYS> select thread#, max(sequence#) from v$archived_log group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14944
# CHECK ARCHIVE LOG DETAILS ON STANDBY DATABASE [SNAPSHOT] SYS> archive log list; Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
1
Next log sequence to archive
2
Current log sequence
2
SYS> select thread#, max(sequence#) from v$archived_log where applied='YES' group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14943
# MAKE LOG SWITCH ON PRIMARY DATABASE SYS> alter system switch logfile; System altered. SYS> alter system switch logfile; System altered. SYS> alter system switch logfile; System altered. SYS> alter system switch logfile; System altered. SYS> select thread#, max(sequence#) from v$archived_log group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14948
# VERIFY WHETHER MRP HAS APPLIED OR NOT ON STANDBY DATABASE SYS> select thread#, max(sequence#) from v$archived_log where applied='YES' group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14943
$ ps -ef | grep mrp oracle
25591 21378
0 04:46 pts/4
00:00:00 grep mrp
# MRP is NOT running
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
As I said above, redo is being received from the primary database, but is not applied. The snapshot standby database should be revert back to a physical Standby then only it would be resynchronized with primary by applying redo data which was earlier shipped from the primary yet not applied. REVERT THE STANDBY DATABASE BACK TO PHYSICAL STANDBY Any updates made to the database while it was operating as a snapshot standby will be rejected. The conversion process does perform shutdown of the standby database. The shutdown is required for the FLASHBACK
DATABASE operation.
DGMGRL> CONVERT DATABASE 'stbycrms' to PHYSICAL STANDBY; Operation requires shutdown of instance "stbycrms" on database "stbycrms" Shutting down instance "stbycrms"... Database closed. Database dismounted. ORACLE instance shut down. Operation requires startup of instance "stbycrms" on database "stbycrms" Starting instance "stbycrms"... ORACLE instance started. Database mounted. Continuing to convert database "stbycrms" ... Operation requires shutdown of instance "stbycrms" on database "stbycrms" Shutting down instance "stbycrms"... ORA-01109: database not open Database dismounted. ORACLE instance shut down. Operation requires startup of instance "stbycrms" on database "stbycrms" Starting instance "stbycrms"... ORACLE instance started. Database "stbycrms" converted successfully
# VERIFY STANDBY DATABASE SYS> select name, db_unique_name, database_role, protection_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
PROTECTION_MODE
--------- ------------------------------ ---------------- -------------------CRMS
stbycrms
PHYSICAL STANDBY MAXIMUM PERFORMANCE
SYS> select open_mode, flashback_on from v$database; OPEN_MODE
FLASHBACK_ON
-------------------- -----------------MOUNTED
NO
$ ps -ef | grep mrp oracle
27524
1
oracle
27544 21378
4 23:25 ?
00:00:06 ora_mrp0_stbycrms
0 23:28 pts/4
00:00:00 grep mrp
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS
# ON PRIMARY DATABSE SYS> select thread#, max(sequence#) from v$archived_log group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14964
# ON STANDBY DATABASE SYS> select thread#, max(sequence#) from v$archived_log where applied='YES' group by thread#; THREAD# MAX(SEQUENCE#) ---------- -------------1
14964
Now MRP process is running. All shipped redo data has been applied on the standby side. Now the Primary database and Standby database is in SYNC. PERFORM A MANUAL FAILOVER
Suppose Primary Database crash and cannot be recovered in a short period, then we need to perform failover operation. After failover operation, we would remove Primary database from Data guard configuration and have to recreate it. If Flashback enabled on the Primary database before the failover operation, you can bring the old Primary back into the configuration as a Standby database. It’s possible to rewind the old Primary database back point in time just before where the failure occurred. The only consideration is you must have enabled Flashback Database on the Primary database before the failover. It’s always good idea and recommended to enable flashback in Standby database also. ENVIRONMENT DETAILS
Database name
: crms
Primary db_unique_name : crms Standby db_unique_name : stbycrms Primary Site
: SERVER1 – 198.168.1.130
Standby Site
: SERVER2 – 198.168.1.131
Standby Database Type
: Physical Standby
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
# PRIMARY DATABASE SERVER SQL> select name, db_unique_name, database_role, protection_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
PROTECTION_MODE
--------- ----------------- ---------------- -----------------CRMS
crms
PRIMARY
MAXIMUM PERFORMANCE
SQL> select switchover_status, flashback_on from v$database; SWITCHOVER_STATUS
FLASHBACK_ON
-------------------- -----------------TO STANDBY
YES
SYS> shut immediate; Database closed. Database dismounted. ORACLE instance shut down.
# STANDBY DATABASE SERVER SQL> select name, db_unique_name, database_role, protection_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
PROTECTION_MODE
--------- ----------------- ---------------- -------------------CRMS
stbycrms
PHYSICAL STANDBY MAXIMUM PERFORMANCE
SQL> select flashback_on from v$database; FLASHBACK_ON -----------------YES
# CONNECTING DGMGRL COMMAND LINE INTERFACE DGMGRL> connect sys/crms@STBY_CRMSDB Connected. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: crms
- Primary database
stbycrms - Physical standby database Fast-Start Failover: DISABLED Configuration Status: ORA-01034: ORACLE not available ORA-16625: cannot reach database "crms"
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DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
# EXECUTE THE FAILOVER DGMGRL> failover to stbycrms; Performing failover NOW, please wait... Failover succeeded, new primary is "stbycrms" DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: stbycrms - Primary database crms
- Physical standby database (disabled)
ORA-16661: the standby database needs to be reinstated Fast-Start Failover: DISABLED Configuration Status: SUCCESS DGMGRL> reinstate database crms; Reinstating database "crms", please wait... Failed. Reinstatement of database "crms" failed
# CONNECT THE NEW PRIMARY DATABASE SYS> select name, db_unique_name, database_role, protection_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
PROTECTION_MODE
--------- ------------------------------ ---------------- -------------------CRMS
stbycrms
PRIMARY
MAXIMUM PERFORMANCE
SYS> select standby_became_primary_scn from v$database; STANDBY_BECAME_PRIMARY_SCN -------------------------221022633 After a failover (when the Physical Standby becomes the Primary), Oracle writes the failover SCN to the control file. We can query STANDBY_BECAME_PRIMARY_SCN column of the V$DATABASE fixed view so that it’s easy to determine at which the old standby database became the new primary database.
# ON OLD PRIMARY DATABASE SYS> startup mount; .. ... Database Mounted. SYS> flashback database to scn 221022633; Flashback complete.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
# TRACE ALERT_LOG INFORMATION $ tail –f alert_crms.log flashback database to scn 221022633 Flashback Restore Start Flashback Restore Complete Flashback Media Recovery Start Serial Media Recovery started .. ... Incomplete Recovery applied until change 221022634 time 11/23/2015 02:05:40 Flashback Media Recovery Complete Completed: flashback database to scn 221022633
# CONVERT THE DATABASE TO A PHYSICAL STANDBY DATABASE SQL> alter database convert to physical standby; Database altered. Above SQL statement will dismount the database after successfully converting the control file to a standby control file.
# SHUT DOWN AND RESTART THE OLD PRIMARY SQL> select status from v$instance; STATUS -----------STARTED SYS> shut immediate; ORA-01507: database not mounted ORACLE instance shut down SQL> startup mount; ORACLE instance stared. .. ... Database Mounted. You can start Redo Apply or real-time apply on the new Physical Standby database. # TO START REDO APPLY SYS> alter database recover managed standby database disconnect; Database altered. # TO START REAL-TIME-APPLY SQL> alter database recover managed standby database using current logfile disconnect; Database altered.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
Note that the sequence was reset to be #1 # ON THE NEW PRIMARY SQL> archive log list; Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
1
Next log sequence to archive
1
Current log sequence
1
SYS> select name, db_unique_name, database_role, protection_level open_mode from v$database; NAME
DB_UNIQUE_NAME
DATABASE_ROLE
PROTECTION_LEVEL
OPEN_MODE
------ -------------- -------------- ------------------- ---------CRMS
stbycrms
PRIMARY
MAXIMUM PERFORMANCE READ WRITE
# EXECUTE THE FOLLOWING QUERY ON THE NEW STANDBY SQL> select process, status, client_process, sequence# from v$managed_standby; PROCESS
STATUS
CLIENT_P
SEQUENCE#
--------- ------------ -------- ---------ARCH
CONNECTED
ARCH
0
ARCH
CONNECTED
ARCH
0
ARCH
CONNECTED
ARCH
0
ARCH
CONNECTED
ARCH
0
RFS
IDLE
UNKNOWN
0
RFS
IDLE
UNKNOWN
0
6 rows selected. # ON THE NEW PRIMARY DATABASE SYS> show parameter log_archive_dest_2; ... Here, redo transport services do not transmit redo data to the new standby database because destination is not available. So configure valid destination to ship redo data to the standby site. SQL> alter system set log_archive_dest_2='service=crmsdb LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=crms' scope=both; System altered. # IF LOG_ARCHIVE_DEST_STAE_2 IS DEFER, EXECUTE FOLLOWING QUERY SYS> alter system set log_archive_dest_stae_2=ENABLE scope=both; System altered. SYS> alter system switch logfile; System altered. SYS> alter system switch logfile; System altered.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
# NOW EXECUTE THE FOLLOWING QUERY ON THE NEW STANDBY SQL> select process, status, client_process, sequence# from v$managed_standby; ...
# CONNECT DGMGRL COMMAND LINE INTERFACE DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: stbycrms - Primary database crms
- Physical standby database (disabled)
ORA-16661: the standby database needs to be reinstated Fast-Start Failover: DISABLED Configuration Status: SUCCESS The next step is to reinstate the failed Primary database DGMGRL> reinstate database crms; ... DGMGRL> show configuration; ... Or, you can use following method also. DGMGRL> remove database crms; Removed database "crms" from the configuration DGMGRL> add database crms as connect identifier is CRMSDB maintained as physical; Database "crms" added DGMGRL> enable database crms; Enabled. DGMGRL> show configuration; Configuration - dgcrms Protection Mode: MaxPerformance Databases: stbycrms - Primary database crms
- Physical standby database
Fast-Start Failover: DISABLED Configuration Status: SUCCESS
Data Guard Broker command line interface (DGMGRL) utility that automates and centralizes Data Guard management. Using DGMGRL we can run consecutive operations such as (switchover/failover) with just one command unlike SQL*Plus interface.
Exploring the Oracle DBA Technology by Gunasekaran ,Thiyagu
DATA GUARD BROKER CONFIGURATION & OPERATIONS | DGMGRL
REMOVE SAFELY DATA GUARD BROKER
DGMGRL> connect sys@CRMSDB Password: DGMGRL> remove configuration; Removed configuration # ON THE PRIMARY DATBASE SYS> show parameter dg_broker; NAME TYPE VALUE ------------------------------------ ----------- -----------------------------dg_broker_config_file1
string
/u01/app/oracle/product/11.2.0 /dbhome_1/dbs/dr1crms.dat
dg_broker_config_file2
string
/u01/app/oracle/product/11.2.0 /dbhome_1/dbs/dr2crms.dat
dg_broker_start
boolean
TRUE
SYS> alter system set dg_broker_start=FALSE scope=both; System altered. $ cd $ORACLE_HOME/dbs $ mv dr1crms.dat dr1crms.dat.bkp $ mv dr2crms.dat dr2crms.dat.bkp # ON THE STANDBY DATABASE SYS> show parameter dg_broker; NAME TYPE VALUE ------------------------------------ ----------- -----------------------------dg_broker_config_file1
string
/u01/app/oracle/product/11.2.0 /dbhome_1/dbs/dr1stbycrms.dat
dg_broker_config_file2
string
/u01/app/oracle/product/11.2.0 /dbhome_1/dbs/dr2stbycrms.dat
dg_broker_start
boolean
TRUE
SYS> alter system set dg_broker_start=FALSE scope=both; System altered. $ cd $ORACLE_HOME/dbs $ mv dr1stbycrms.dat dr1stbycrms.dat.bkp $ mv dr2stbycrms.dat dr2stbycrms.dat.bkp DGMGRL> show configuration; Error: ORA-16525: the Data Guard broker is not yet available Configuration details cannot be determined by DGMGRL We have safely removed Data Guard broker configuration. Nice link for DGMGRL commands given here.
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