Transcript Data Guard Technology Overview

Agenda
 Data Guard Architecture & Features
 Data Guard Success Stories & Benefits
What is Oracle Data Guard?
 Oracle’s disaster recovery solution for Oracle data
 Feature of Oracle Database Enterprise Edition
 Automates the creation and maintenance of one or
more transactionally consistent copies (standby) of the
production (or primary) database
 If the primary database becomes unavailable (disasters,
maintenance), a standby database can be activated and
assume the primary role
Oracle Data Guard Focus
 Data Failures & Site Disasters:
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Data Protection
Data Availability
Data Recovery
All 3 are important!
Data is the core asset of
the enterprise!
• Also addresses human errors & planned maintenances
Data Guard Overview
Clients
Clients
Primary
Site
Data Changes
Data Guard Broker
Standby
Site
Data Guard Configuration
Primary Site
Standby Site A
Standby Site B
Standby
Database
Primary
Database
Standby
Database
 Managed as a single configuration
 Primary and standby databases can be Real Application Clusters
or single-instance Oracle
 Up to nine standby databases supported in a single configuration
Oracle Data Guard Architecture
Physical Standby
Database
Sync or Async
Redo Shipping
Backup
Production
Database
Redo Apply
Network
DIGITAL DATA STORAGE
DIGITAL DATA STORAGE
Broker
Transform
Redo to SQL
Logical Standby
Database
SQL
Apply
Open for
Reports
Additional
Indexes & MVs
Data Guard Redo Apply
Primary
Database
Data Guard
Broker
Physical Standby
Database
Redo Apply
Network
Redo Shipment
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Backup
DIGITAL DATA STORAGE
Standby
Redo Logs
Physical Standby Database is a block-for-block copy of the primary database
Uses the database recovery functionality to apply changes
Can be opened in read-only mode for reporting/queries
Can also be used for backups, offloading production database
Data Guard SQL Apply
Additional
Indexes &
Materialized Views
Primary
Database
Data Guard
Broker
Logical Standby
Database
Transform Redo
to SQL and Apply
Continuously
Open for Reports
Network
Redo Shipment
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Logical Standby Database is an open, independent, active database
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Standby
Redo Logs
Contains the same logical information (rows) as the production database
Physical organization and structure can be very different
Can host multiple schemas
Can be queried for reports while logs are being applied via SQL
Can create additional indexes and materialized views for better query performance
Protection from Human Errors
and Data Corruptions
Primary Site
Optional Delayed
Apply
Standby Site
Data Changes
 Application of changes received from the primary can be delayed at standby
to allow for the detection of user errors and prevent standby to be affected
 Administrators may choose not to configure any delay – if both primary and
standby are affected, then they can be simply flashed back [10g]
 The apply process also revalidates the log records to prevent application of
any log corruptions
Switchover and Failover
 Primary and Standby role transitions
 Switchover
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Planned role reversal
No database reinstantiation required
Used for maintenance of OS or hardware
 Failover
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Unplanned failure (e.g. disasters) of primary
Primary database must be reinstantiated / flashed back [10g]
 Initiated using simple SQL / GUI interface
 Data Guard automates the processes involved
Flexible Data Protection Modes
Protection Mode
Risk of Data Loss
Redo Shipment
Maximum Protection
Zero Data Loss
Double Failure Protection
Synchronous redo
shipping to 2 sites
Maximum Availability
Zero Data Loss
Single Failure Protection
Synchronous redo
shipping
Maximum Performance
Minimal data loss –
usually 0 to few seconds
Asynchronous redo
shipping
Balance cost, availability, performance, and transaction protection
Automatic Resynchronization
 Network connectivity problems may occur
 Data Guard automatically resynchronizes standbys after
network connectivity restored
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Implicit
 ARCH process idling away on the primary ‘pings’ all standbys
on a regular basis to see if they are missing any redo data
 If so it sends them the missing redo data
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Explicit
 Gap discovered during apply process in physical standby
 Based on FAL_SERVER and FAL_CLIENT settings, primary
notified, and it sends missing redo data
Data Guard Broker
 Distributed management framework that automates
and centralizes the creation, maintenance, and
monitoring of Data Guard configurations
 Management operations can be performed locally or
remotely through easy-to-use interfaces:
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Oracle Enterprise Manager
Data Guard Broker’s command-line interface
Real Time Apply
 Redo data is applied to the standby database as soon as it is
received from the primary database
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Without this support, apply has to wait till an archivelog is
created on the standby database
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Enables real-time reporting, faster switchovers/failovers
 For Redo Apply:
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING
CURRENT LOGFILE
 For SQL Apply:
ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE
 When real time apply is enabled, RECOVERY_MODE column in
V$ARCHIVE_DEST_STATUS displays “MANAGED REAL TIME
APPLY”
Real Time Apply Architecture
An up-to-date
Physical/Logical
Standby
Database
Oracle Net
Transactions
LGWR
Online
Redo
Logs
Primary
Database
MRP/ LSP
RFS
Standby
Redo
Logs
ARCH
Real Time
Apply
ARCH
Archived
Redo Logs
Archived
Redo Logs
SQL Apply: Zero Downtime Instantiation
 Logical standby database can now be created
from an online backup of the primary database,
without shutting down or quiescing the primary
database
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No shutdown implies no downtime of production
system
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No quiesce implies no wait on quiesce and no
dependence on Resource Manager
Example – Ease of Use
 Switchover using Enterprise Manager is now
literally two mouse clicks
Switched!
Agenda
 Data Guard Architecture & Features
 Data Guard Success Stories & Benefits
Data Guard Customers
Transportation
Telecom
Financial/
Insurance
Utilities
Government
Manufacturing
Health Care
Other Industries
e-Commerce
Usage Examples
Chicago
Dallas
Primary
Database
Standby
Database
Standby
Database
Primary
Database
Maximize primary and
standby resources
Example A
Example B
Standby machine must be powerful
enough to support multiple production
instances after switchover / failover
Primary
Site A
Primary
Database
Primary
Site B
Primary
Database
Primary
Site C
Primary
Database
Standby
Database
Standby
Database
Standby
Database
Standby Site
Data Guard Usage Examples
Primary Site
Standby Site A
Synchronous transport
LAN attached
Used to offload backups
First choice for switchover candidate
Standby Site B
Synchronous transport
LAN attached
Used to offload reporting
Standby Site C
Example C
Asynchronous transport
WAN attached
Delayed apply
Provides DR and data protection
What Fidelity Says
 “Data Guard automates disaster-recovery procedures
and reduces Fidelity's exposure to data loss by an order
of magnitude compared to previous approaches.”
Jonathan Schapiro
Vice President
Data Architecture & Services
Global Equity Trading & Technology
QUESTIONS
ANSWERS