Transcript Understanding the Oracle Data Guard Architecture

Understanding the Oracle
Data Guard Architecture
Copyright © 2006, Oracle. All rights reserved.
Objectives
After completing this lesson, you should be able to do the
following:
• Describe the Data Guard architecture
• Explain the operational requirements of Data Guard
• Describe how Data Guard processes, transports, and
applies redo logs
• Describe standby database modes
2-2
Copyright © 2006, Oracle. All rights reserved.
Data Guard Operational Requirements: Hardware
and Operating System
• The hardware can be different for the primary and
standby databases.
• The operating system and platform architecture for the
primary and standby databases must be the same.
• The operating system releases for the primary and
standby databases can be different.
• If all databases are on the same system, verify that the
OS allows you to mount more than one database with
the same name.
2-3
Copyright © 2006, Oracle. All rights reserved.
Data Guard Operational Requirements: Oracle
Database Software
• Same release of Oracle Database Enterprise Edition
must be installed for all databases.
• SYSDBA privileges are required for the accounts used to
manage the database instances.
• Each database must have its own control file.
• Primary database must operate in ARCHIVELOG mode.
• Enable FORCE LOGGING on the primary database before
taking data file backups for standby creation.
• If any databases use ASM and/or OMF, all should use
the same combination.
2-4
Copyright © 2006, Oracle. All rights reserved.
Oracle Data Guard: Architecture
Primary
database
transactions
MRP or
LSP
(MRP only)
LGWR LNSn
RFS
Oracle net
Online
redo
logs
Standby
database
(Real-time
apply)
Standby
redo logs
Backup
Reports
FAL
ARC0
ARC0
Archived redo
logs
2-6
Copyright © 2006, Oracle. All rights reserved.
Archived redo
logs
Primary Database Flow
Primary
database
transactions
MRP or
LSP
(MRP only)
LGWR LNSn
RFS
Oracle net
Online
redo
logs
Standby
database
(Real-time
apply)
Standby
redo logs
Backup
Reports
FAL
ARC0
ARC0
Archived redo
logs
2-7
Copyright © 2006, Oracle. All rights reserved.
Archived redo
logs
Standby Database Flow
Primary
database
transactions
MRP or
LSP
(MRP only)
LGWR LNSn
RFS
Oracle net
Online
redo
logs
Standby
database
(Real-time
apply)
Standby
redo logs
Backup
Reports
FAL
ARC0
ARC0
Archived redo
logs
2-8
Copyright © 2006, Oracle. All rights reserved.
Archived redo
logs
Standby Redo Logs
Standby
redo logs
Redo from
primary database
RFS
Archived
redo logs
ARC0
MRP/LSP
Standby database
2-9
Copyright © 2006, Oracle. All rights reserved.
Physical Standby Database:
Redo Apply Architecture
Production
database
Physical standby
database
Redo
transport
Redo
apply
Redo
stream
Backup
Primary
database
2 - 10
Physical standby
database
Copyright © 2006, Oracle. All rights reserved.
Logical Standby Database:
SQL Apply Architecture
Production
database
Logical standby
database
Redo transport
SQL
Apply
Transform redo
information into
SQL
Reports
Primary
database
2 - 12
Logical standby
database
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SQL Apply Process: Architecture
Reader
Preparer
Log Mining
Builder
Shared
pool
Redo
records
Redo data from
primary database
LCR
LCR
:
Logical change records not
grouped into transactions
Transaction
groups
Apply processing
Applier
Data files
2 - 13
Analyzer
Coordinator
Transactions to
be applied
Transactions
sorted in
dependency
order
Copyright © 2006, Oracle. All rights reserved.
Real-Time Apply
RFS
Primary
database
MRP or LSP
Standby
redo log
files
ARC0
Archived
redo log
files
2 - 14
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Standby
database
Setting the DB_UNIQUE_NAME Parameter
San Francisco
SF1_DB
DB_UNIQUE_NAME = SF1_DB
2 - 16
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Specifying Role-Based Destinations
Primary
database
Standby
database
Not used
LOG_ARCHIVE_DEST_2= location=
"/u01/app/oracle/oradata/orcldg2/arc",
valid_for=(STANDBY_LOGFILE,STANDBY_ROLE)
DB_UNIQUE_NAME = HRDB2
2 - 17
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Combinations for VALID_FOR
2 - 19
Combination
Primary Physical Logical
ONLINE_LOGFILE, PRIMARY_ROLE
Valid
Ignored
Ignored
ONLINE_LOGFILE, STANDBY_ROLE
Ignored
Ignored
Valid
ONLINE_LOGFILE, ALL_ROLES
Valid
Ignored
Valid
STANDBY_LOGFILE,STANDBY_ROLE
Ignored
Valid
Valid
STANDBY_LOGFILE, ALL_ROLES
Ignored
Valid
Valid
ALL_LOGFILES, PRIMARY_ROLE
Valid
Ignored
Ignored
ALL_LOGFILES, STANDBY_ROLE
Ignored
Valid
Valid
ALL_LOGFILES, ALL_ROLES
Valid
Valid
Valid
Copyright © 2006, Oracle. All rights reserved.
Identifying Destination Settings
SQL> SELECT DEST_ID,VALID_TYPE,VALID_ROLE,VALID_NOW
2 FROM V$ARCHIVE_DEST;
DEST_ID VALID_TYPE
VALID_ROLE
VALID_NOW
------- --------------- ------------ -------------1 ALL_LOGFILES
ALL_ROLES
YES
2 STANDBY_LOGFILE STANDBY_ROLE WRONG VALID_TYPE
3 ONLINE_LOGFILE STANDBY_ROLE WRONG VALID_ROLE
4 ALL_LOGFILES
ALL_ROLES
UNKNOWN
5 ALL_LOGFILES
ALL_ROLES
UNKNOWN
6 ALL_LOGFILES
ALL_ROLES
UNKNOWN
7 ALL_LOGFILES
ALL_ROLES
UNKNOWN
8 ALL_LOGFILES
ALL_ROLES
UNKNOWN
9 ALL_LOGFILES
ALL_ROLES
UNKNOWN
10 ALL_LOGFILES
ALL_ROLES
UNKNOWN
11 ALL_LOGFILES
ALL_ROLES
YES
11 rows selected.
2 - 20
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Standby Redo Log Configuration
Online
redo
logs
Standby
redo
logs
Redo
shipment
RFS
Primary
database
2 - 21
Standby
database
Copyright © 2006, Oracle. All rights reserved.
Using SQL to Add Standby Redo Logs
• Use the ALTER DATABASE statement to create the
standby redo log files:
SQL> ALTER DATABASE ADD STANDBY LOGFILE
2 ('/oracle/oradata/orcl/log1c.rdo',
3 '/oracle/oradata/orcl/log2c.rdo') SIZE 500K;
• Add members to a group with the following statement:
SQL> ALTER DATABASE ADD STANDBY LOGFILE MEMBER
2 '/oracle/oradata/orcl/log2b.rdo' TO GROUP 2;
• View information about the groups as follows:
SQL> SELECT * FROM v$standby_log;
SQL> SELECT * FROM v$logfile
2 WHERE type = 'STANDBY';
2 - 22
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Using Enterprise Manager
to Add Standby Redo Logs
2 - 23
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Standby Database Modes
You can maintain the standby data in one of the following
modes:
• For physical standby databases
– Redo Apply
– Open read-only mode
• For logical standby databases
– Open read/write mode
2 - 24
Copyright © 2006, Oracle. All rights reserved.
Summary
In this lesson, you should have learned how to describe
the following:
• Data Guard architecture processes
• Operational requirements of a Data Guard environment
• How Data Guard processes, transports, and applies
redo logs
• Modes of standby databases and when to use each
mode
2 - 26
Copyright © 2006, Oracle. All rights reserved.
Practice 2-1: Architecture Review
This practice covers the following topics:
• Reviewing the Oracle Data Guard architecture
• Reviewing the processes that Data Guard uses to
transport and apply redo logs
• Reviewing the modes that are used to recover a
primary database
2 - 27
Copyright © 2006, Oracle. All rights reserved.
Practice 2-2: Installing the
Oracle Management Agent
This practice covers the following topics:
• Installing the Oracle Management Agent
• Configuring monitoring credentials for your database
2 - 28
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Practice 2-3: Configuring Your Primary Database
This practice covers the following topics:
• Reviewing your primary database configuration
• Configuring your primary database in preparation for
creating a Data Guard configuration
2 - 29
Copyright © 2006, Oracle. All rights reserved.