Data Guard25 August

Oracle Data Guard 11g Release 2 with Oracle Enterprise Manager 11g Grid Control


Introduction to High AvailabilityData Guard ConceptsManaging Data Guard with OEM Setup Data Guard without OEM

Introduction to High Availability Availability is the degree of accessibility of an application, service or

system. It is measured as the percentage of uptime in a given year.

Characteristics of a highly available systemso Reliabilityo Resiliencyo No single point of failure (SPOF)o Recoverabilityo Timely error detectiono Continuous operation

Availability % Annual downtime Monthly downtime*Weekly downtime90% 36.5 days 72 hours 16.8 hours95% 18.25 days 36 hours 8.4 hours98% 7.30 days 14.4 hours 3.36 hours99% 3.65 days 7.20 hours 1.68 hours99.50% 1.83 days 3.60 hours 50.4 minutes99.80% 17.52 hours 86.23 minutes 20.16 minutes99.9% ("three nines") 8.76 hours 43.2 minutes 10.1 minutes99.95% 4.38 hours 21.56 minutes 5.04 minutes99.99% ("four nines") 52.6 minutes 4.32 minutes 1.01 minutes99.999% ("five nines") 5.26 minutes 25.9 seconds 6.05 seconds99.9999% ("six nines") 31.5 seconds 2.59 seconds 0.605 seconds

Introduction to High Availability

Service Level Agreement (SLA): agreement between two parties specifying levels of availability, performance or operation. In the contract the level of each service should be clearly defined.

Recovery Time Objective (RTO): maximum amount of time that application, service or system can be down before the organization starts suffering unacceptable consequences.

Recovery Point Objective (RPO): maximum amount of data that can be lost without harm to the organization as a result from failure of an application, service or system.

Finalize with all stake holders prior to DR planning and implementation

Introduction to High Availability

UnplannedSite failureCluster failureComputer failureSystem failureStorage failureData corruptionHuman errorHang or slowdownNatural disaster

PlannedSystem and

database changes

Data changesApplication

changes

Resiliency and protection from failures

Introduction to High Availability Present demand for high availability Oracle HA solutions as response

Oracle RAC Oracle Data Guard Oracle Flashback Oracle Streams Oracle Goldengate

How we benefit leveraging Oracle RAC, Oracle Data Guard and Oracle Flashback implementing MAA?

How Oracle RAC, Oracle Data Guard, Oracle Flashback work in tandem in implementing MAA solutions.

Data Guard Configurations Fast Start failover Flashback as a way to avoid restoring the primary from backup in case

of a failover, converting it to standby and synching it with the new primary.

OEM as a primary tool for managing MAA solutions.

Data Guard ConceptsOracle Data Guard provides the managements,

monitoring and automation software to create and maintain one or more standby databases to protect Oracle data from failures, disasters, human errors and data corruption

Data Guard configuration consist of one primary database and one or more standby databases. The databases in a Data Guard configuration may be dispersed geographically.

Managing primary and standby databases can be done using SQL command-line interfaces, Data Guard broker interfaces or using a GUI interface provided with OEM Grid Control.

Data Guard ConceptsPrimary database: accessed by most

applications, can be a single instance or RAC database

Standby database: consistent copy of the primary database. Maintained automatically using redo data. Can be a single-instance or RAC database.

Data Guard ConceptsPhysical Standby database

• Provides a block-for-block physically identical copy of the primary database.

• Synchronized through Redo Apply. Redo records are shipped and applied to the standby database.

• Benefits:1. Switchover and failover2. Standby database can be

open in read only mode while redo apply continues ( Active data Guard). Can not be used when with reporting tools requiring read-write access such as repository creation.

3. Can be used as a robust DR implementation.

Logical Standby database• Provides a logically (transactionally)

identical copy of the primary database. Contains the same logical information as the primary database although the physical organization and structure can be different.

• Synchronized via SQL Apply. Redo records are shipped to the standby database and mined and applied as a SQL to the standby database.

• Additional structures can be created to optimize the reporting workload.

• Some restrictions on data types, types of tables and types of DDL and DML operations.

• Benefits:1. Switchover and failover2. Standby database open in read-write

mode. Offload production when apps need read-write access but do not modify primary data such as when repositories are created.

3. Can be used to perform upgrades to primary database with near zero downtime.

Data Guard ConceptsSwitchover : the primary database

transition to a standby role and the standby database transition to the primary role. It is used during the course of a planned maintenance of the primary database and ensure no data loss. Final EOR is applied on the standby database.

Failover: Occurs when the primary database is unavailable. Failover is performed only in case of a failure of the primary database and the failover results in a transition of a standby database to the primary role. Final EOR is not applied on the standby database.

Data Guard Concepts Maximum availability: Archive destination is mandatory with log

writer sync and affirm. Set by ‘alter database set standby to maximize availability’. Transactions do not commit until all redo data needed to recover the transactions has been written to the online redo log and to the standby redo log on at least one synchronized standby database. Ensures zero data loss except in case of certain failures when standby can not receive redo from primary.

Maximum performance: Archive destination is either mandatory/optional and transport is log writer or archive process and synchronous or asynchronous. Set by ‘alter database set standby to maximize performance’ .Is the default protection mode. Transactions commit as soon as redo data generated by those transactions has been written to the online log. Offers less data protection than maximum availability mode.

Maximum protection: Archive destination is mandatory with log writer sync and affirm. Set by ‘alter database set standby to maximize protection’. Redo data needed to recover as a transaction must be written to both the online redo log and to the standby database redo log on at least one synchronized standby database before the transaction commits. Ensures zero data loss.

Data Guard ConceptsNew features in 11gR1

• Support up to 9 standby databases.

• Real time query capability of physical standby database (New Active Data Guard) feature.

• User configurable conditions to initiate fast-start failover.

• New Snapshot Data Guard feature.

• Transport of redo data using SSL

• Support of TDE with Data Guard SQL Apply.

New features in 11gR2• Support up to 30

standby databases.• Integrated support

for Application failover.

• Compressed table support in logical standby databases.

• Automatic redo corruption detection and repair.

Data Guard Concepts

Lets put it together…

Managing Data Guard with OEM Add physical or logical standby database.

Crate a new physical or logical standby database Add an existing standby database for management with Data Guard Broker. Flexible options for creating standby database based on RMAN features for

backup and cloning. Direct cloning using the primary database as a source. Using a staged backup

Created with create standby database wizard Created as level 0 and level 1 regular backup

Monitor performance of a standby database Redo Generation Rate Redo Apply Rate Transport Lag Apply Lag

Monitor the archiving and application of redo log Verify structure of a Data Guard Perform Switchover or Failover Set the type of a standby database (Active Data Guard &

Snapshot Data Guard) Manage a Data Guard configuration and set fast-start failover.

Managing Data Guard with OEM Add physical or logical standby

database.

Managing Data Guard with OEM Add physical standby database.

Managing Data Guard with OEM Add physical standby database.

◦ After adding a standby database new options under Data Guard hyperlink appears◦ What we gain?

Managing Data Guard with OEM Verify structure of a Data Guard

Managing Data Guard with OEM Verify structure of a Data Guard What OEM do for us? What we need to do if we do it ourselves?

InitializingConnected to instance oel55.gj.com:D11PStarting alert log monitor...Updating Data Guard link on database homepage...Skipping verification of fast-start failover static services check.Data Protection Settings: Protection mode : Maximum Performance Redo Transport Mode settings: D11P: ASYNC D11P1: ASYNC Checking standby redo log files.....OKChecking Data Guard status D11P : Normal D11P1 : NormalChecking inconsistent propertiesChecking agent statusChecking applied log on D11P1...OKProcessing completed.

Managing Data Guard with OEM Monitor performance of a standby database

Managing Data Guard with OEM Manage a Data Guard configuration

Managing Data Guard with OEM Manage a Data Guard configuration – Perform a

switchover


Failover


Failover & Reinstate the old physical database

Managing Data Guard with OEM Manage a Data Guard configuration –

Configure fast-start failovero Select a standby database as a target for the

fast-start failovero Configure observer ( specify observer host and

observer ORACLE_HOME)o Set failover propertieso Enable flashback loggingo Enable observero Fast start failover does NOT work in maximum

protection role. In 10g only max availability role was supported for FSFO. Since 11g both maximum performance and maximum availability are supported.


Configure Observer


Enable flashback logging


complete fast-start failover configuration

Managing Data Guard with OEM Manage a Data Guard configuration – Create

logical standby database• Specify ‘Create new logical standby database’ and follow

similar steps as create a physical standby database.• SQL Apply Unsupported tables• Specify Backup options• Specify Database location• Specify File locations• Specify Configuration

Managing Data Guard with OEM Manage a Data Guard

configuration – Create logical standby database

SQL Apply Unsupported tables

Managing Data Guard with OEM Manage a Data Guard

configuration – Create logical standby database

Managing Data Guard with OEM Monitor a Data Guard configuration

Managing Data Guard with OEM Monitor a Data Guard configuration

Redo logs archived and applied

Managing Data Guard with OEM Active Data Guard

What is Active Data Guard? How to set Active Data Guard?

Managing Data Guard with OEM Snapshot Data Guard

What is Snapshot Data Guard? How to set Snapshot Data Guard?

Set Redo Transport Off Enable Flash back Database Set Redo Transport On Use Convert to toggle between Snapshot Database and Physical Database

Managing Data Guard with OEM Manage a Data Guard configuration – Add

existing Data Guard with OEM

• Configuring Data Guard Broker with OEM Grid Control to manage an existing Data Guard by enabling Data Guard Broker• Select ‘Add standby database screen’• Specify the standby database to be enabled for

management with Data Guard Broker and specify the additional properties (login credentials, archive destination, FRA).

• Review the changes and confirm the creation of a Data Guard Broker configuration enabling us to manage the database via OEM or DGMGRL.


Remove Data Guard configuration• Removing a standby database from Data

Guard Broker.• Select a standby database you want removed from the

Data Guard configuration• Press REMOVE button.• Acknowledge that you want to remove it at the

confirmation page (database remains on ASM or disk).

• Remove a Data Guard configuration• Click at the ‘Remove Data Guard Configuration’ link• Acknowledge that you want to remove the

configuration at the confirmation page.• When complete you are returned to the Data Guard

home page.

Managing Data Guard without OEM Setup Data Guard without OEM

Configure primary database Configure Oracle NET Prepare standby site

Create directory structures on the standby site Copy password file from primary database Create init file Set-up environment variables on the standby site

Create the standby database using the new 11g RMAN feature for duplicating a database using an active primary database.

Verify that the standby database is correct and redo data is received and archived on the standby database.

Create a data Guard Broker configuration using DGMGRL utility

Managing Data Guard without OEM Configure primary database

Make sure the primary database has a spfile; Enable force logging on primary:

SQL> alter database force logging; Configure database to have standby redo logs on

primary: SQL> alter database add standby logfile;

Configure database initialization parameters LOG_ARCHIVE_CONFIG and LOG_ARCHIVE_DEST_n on primary:SQL>alter system set log_archive_config=’dg_config=(d11p,d11s)’;SQL>alter system set log_archive_dest_2=’service=d11s ASYNC valid_for=(ONLINE_LOGFILE,PRIMARY_ROLE) db_unique_name=d11s’;

Configure the primary database in ARCHIVELOG modeSQL> alter database arhivelog;

Managing Data Guard without OEM Configure Oracle NET

Create an alias for the standby in tnsnames.ora◦ D11S =◦ (DESCRIPTION =◦ (ADDRESS_LIST =◦ (ADDRESS = (PROTOCOL = TCP)(HOST = oel55.gj.com)(PORT = 1521))◦ )◦ (CONNECT_DATA =◦ (SERVER = DEDICATED)◦ (SERVICE_NAME = D11S)◦ )◦ )

On the standby site configure an entry for the standby database in

listener.ora◦ SID_LIST_LISTENER = ◦ (SID_LIST = ◦ (SID_DESC = ◦ (GLOBAL_DBNAME = D11S)◦ (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1 )◦ (SID_NAME = D11S)◦ )◦ )

Managing Data Guard without OEM

Prepare Standby site for D11S standby database

Create the directories required for the standby database D11S.

Copy the orapw from the primary site and rename it to orapwD11S to match the name of the standby instance.

Create initD11S.ora with a line db_name=D11S

Set environment variables. Start the standby database in nomount

using the initD11S.ora


Run RMAN to create the standby database D11S from D11P

On the primary site: Run RMAN for creating the standby database

rman target / auxiliary sys@D11S execute the script:

run { allocate channel d11gp1 type disk; allocate channel d111p2 type disk; allocate auxiliary channel stby type disk; duplicate target database for standby from active database spfileparameter_value_convert ‘d11p,d11s’set db_unique_name=’d11’set db_file_name_convert=’/d11p/’,’/d11s/’set log_file_name_convert=’/d11p/’,’/d11s/’set log_archive_max_processe=’5’set fal_client=’d11s’set fal_server=’d11p’set standby_file_management=’AUTO’set log_archive_config=’dg_config=(d11p,d11s)’set log_archive_dest_2=’service=d11p SYNC valid_for=(ONLINE_LOGFILE,PRIMARY_ROLE) db_unique_name=d11p’; }


Verify the standby database creation. Make sure redo is received and

archived on standbyOn the standby database check the sequence#

of the last received log by issuing: SQL> select sequence#, first_time, next_time, applied from v$archive_log order by sequence#;

Perform a log switch on the primarySQL> alter system switch logfile;

Check if the log is received and archived on the standby site by verifying that the sequence is increments by one.SQL> select sequence#, first_time, next_time, applied from v$archive_log order by sequence#;

Managing Data Guard without OEM Create a data Guard Broker configuration

using DGMGRL utility Set the DG_BROKER_START=TRUE on both primary and standby database

SQL> alter system set dg_broker_start=true;

Modify the listener to work with Data Guard Broker by adding a static entry for DGMGRL to avoid ORA-12154 errors. Errors can be observed on startup of the standby database after performing a switchover. Reload the listener.

SID_LIST_LISTENER =

(SID_LIST =

(SID_DESC =

(GLOBAL_DBNAME = D11P_DGMGRL)

(ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1 )

(SID_NAME = D11P)

)

(SID_DESC =

(GLOBAL_DBNAME = D11S_DGMGRL)

(ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1 )

(SID_NAME = D11S)

)

)

Invoke the DGMGRL and connect to the primary database. Create the Data Guard Broker configuration that includes a profile for the primary database.

DGMGRL>create configuration ‘DR1’ as primary database is ‘D11P’ connect identifier is D11P;

Add the physical standby database to the broker configuration.

DGMGRL>add database ‘D11S’ as connect identifier is D11S;

Enable the configuration.

DGMGRL> enable configuration;

Verify the configuration.

DGMGRL> show configuration;


using DGMGRL utility How to setup Active Data Guard? On the standby database perform:

DGMGRL> edit database ‘D11S’ set state=’apply-off’;

SQL>alter database open read only;

DGMGRL>edit database ‘D11S’ set state=’apply-on’;


using DGMGRL utilityHow to enable Fast start failover?

Enable flashback on the primary and standby databases

Verify we configured standby redo log files Ensure the LogXptMode Property is set to SYNC.

These commands will succeed only if database is configured with standby redo logs.DGMGRL> EDIT DATABASE D11P SET PROPERTY 'LogXptMode'='SYNC';DGMGRL> EDIT DATABASE D11S SET PROPERTY 'LogXptMode'='SYNC';

Specify the FastStartFailoverTarget propertyDGMGRL> EDIT DATABASE D11P SET PROPERTY FastStartFailoverTarget='D11S';DGMGRL> EDIT DATABASE D11S SET PROPERTY FastStartFailoverTarget='D11P';

Managing Data Guard without OEM Create a data Guard Broker configuration using DGMGRL

utilityHow to enable Fast start failover? (cont.)

Make sure maximum protection is not set. Enable Fast Start Failover

DGMGRL>enable fast_start failover Verify configuration

DGMGRL>show fast_start failoverDGMGRL>show database D11PDGMGRL>show database D11S

Perform switchover to the standby database DGMGRL>switchover to D11S;

Check changes to the configurationDGMGRL>show configuration;SQL> select database_role from v$database;

Perform switchover to the original primaryDGMGRL>switchover to D11P;

Check changes to the configurationDGMGRL>show configuration;SQL> select database_role from v$database;


Questions?

Data Guard25 August

Technology

Transcript of Data Guard25 August