Etc Dataguard

8/8/2019 Etc Dataguard

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Oracle Data GuardEnsuring Disaster Recovery for Enterprise Data

Enterprise Technology Centre


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Introducing Oracle Data Guard

Oracle Data Guard is the most

effective and comprehensive

Disaster Recovery solutionavailable today for enterprise data


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Oracles High Availability (HA)Solution Stack

System

Failure

Data Failure

& Disaster

Human Error

Real Application ClustersContinuous Availability for all Applications

Data GuardZero Data Loss

Flashback QueryEnable Users to Correct their Mistakes

System

Maintenance

Data

Maintenance

Dynamic ReconfigurationCapacity on Demand without Interruption

Online RedefinitionAdapt to Change Online

Unplanned

Downtime

Planned

Downtime


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Oracle Data Guard Focus

Data Failures & Site Disasters:

Eliminates and reduces downtimes that could occur

because of human errors & planned maintenances

Data Protection

Data Availability Data Recovery

Data is the core asset of

the enterprise!


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What Is Oracle Data Guard?

Database software infrastructure that automates the

creation and maintenance of a duplicate, or standby

copy, of the production (or primary) database

If the primary database becomes unavailable

(disasters, maintenance), the standby database can

be activated and can take over the data serving

needs of the enterprise


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How Does It Work?

As primary database is modified, redo data ispropagated to standby databases

Standby databases kept synchronized with primary

Primary database is open and active; standbydatabase is either in recovery or open read-only /read-write

Standby database can be transitioned to the primaryrole as necessary


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Data Guard Configuration

Managed as a single configuration

Primary and standby databases can be single-instance Oracle or

Real Application Clusters

Up to nine standby databases supported in a single configuration

Primary

Database

Standby

Database

StandbySite A

Standby

Database

StandbySite B

PrimarySite


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Oracle Data Guard Architecture

NetworkBroker

ProductionDatabase

LogicalStandbyDatabase Open for

Reports

SQLApply

OptionalDelay

TransformRedo to SQL

AdditionalIndexes & MVs

PhysicalStandbyDatabase

OptionalOptionalDelayDelay

DI

ITALDATA STORA

DI

ITALDATA STORA

Backup

Redo Apply

Sync or AsyncRedo Shipping


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Data Guard Redo Apply

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 perform backup, offloading production database

Data Guard Broker

PrimaryDatabase

Physical StandbyDatabase

Optional

Delay


Network

Redo Apply

DIGITA

DATA STORAG

Backup


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Data Guard SQL Apply

Logical Standby Database is an open, independent, active database

Contains the same logical information (rows) as the production database

Physical organization and structure can be very different

Can be queried for reports while logs are being applied via SQL

Can create additional indexes and materialized views for better query performance

Optional

Delay

AdditionalIndexes &

Materialized Views


Network

ContinuouslyOpen for Reports

Transform Redoto SQL and Apply

Data Guard BrokerPrimary

Database Logical StandbyDatabase


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Standby Databases Are Not Idle

Standby database can be used to

offload the primary database, increasing the ROI

Standby

Server

Standby

Database

Read-Only / Read-Write

Reporting

BackupsTape


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Cascading Standby Database

Standby database that receives its redo data from another

standby database and not from the original primary database

Primary database sends a set of redo data to only selectedstandby databases and not to all standby databases

Reduces the load on the primary system, and also reduces

network traffic and use of valuable network resources around theprimary site


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Protection from Human Errorsand Data Corruptions

The application of changes received from the primary can be

delayed at standby to allow for the detection of user errors andprevent standby to be affected

Primary Site

Standby

Database

Standby Site

ProductionDatabase

Optional Delayed

Apply


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Switchover and Failover

Primary and Standby role transitions

Switchover

Planned role reversal

No database reinstantiation required

Used for maintenance of OS or hardware

Failover

Unplanned failure (e.g. disasters) of primary

Primary database must be reinstantiated

Initiated using simple SQL / GUI interface


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Flexible Data Protection Modes

ProtectionMode Risk of Data Loss Redo Shipment

Maximum Protection Zero

Double Failure Protection

Synchronous redo

shipping to 2 sites

Maximum Availability Zero

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


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Maximum Protection ModeMaximum Protection Mode

Highest level of data protection

Enforces protection of every transaction

If last standby is unavailable, processing stops at primary

Good for financial systems where no data loss is acceptable


Maximum Protection Zero

Double Failure Protection

Synchronous redo

shipping to 2 sites

ALTER DATABASE SET STANDBY TO MAXIMIZE PROTECTION;


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Maximum Availability ModeMaximum Availability Mode

Enforces protection of every transaction

If last standby is unavailable, processing continues at primary

When it is re-available, synchronization is automatic


Maximum Availability Zero

Single Failure Protection

Synchronous redo

shipping

ALTER DATABASE SET STANDBY TO MAXIMIZE AVAILABILITY;


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Maximum Performance ModeMaximum Performance Mode

Highest level of performance

Protects from failure of any single component

Least impact on production system

Useful for applications that can tolerate some data loss


Maximum Performance Minimal data loss

usually 0 to few seconds

Asynchronous redo

shipping

ALTER DATABASE SET STANDBY TO MAXIMIZE PERFORMANCE;


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Oracle 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 the Broker's easy-to-use interfaces:

GUI-based Oracle Data Guard Manager

Data Guard command-line interface


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Data Guard Manager

Simple, easy-to-use management and monitoring interface


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Local and Remote Standby Databases

Oracle Data Guard configuration can support both local andremote standby databases

Local standby database Appropriate for highest data protection modes

LAN links are cheap, reliable, have high bandwidth and low latency Switchover operations are very fast

Remote standby database Best solution for disaster recovery

WAN links are generally more expensive, less reliable, have lowerbandwidth and higher latency than LAN links

Suitable for highest performance asynchronous data protection mode


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Usage Example

Primary

Database

PrimaryS

ite

Standby

Database

StandbySite A Synchronous transport

LAN attachedUsed to offload backups

First choice for switchover candidate

Standby

Database

StandbySite B

Synchronous transport

LAN attachedUsed to offload reporting

Standby

Database

StandbySite C

Asynchronous transport

WAN attached

Delayed apply

Provides DR and data protection


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Oracle Data Guard and RealApplication Clusters

Data Guard and Real Application Clusters are complementary and

should be used together

Real Application Clusters provides high availability

Provides rapid and automatic recovery from node failures or aninstance crash

Provides increased scalability

Data Guard provides disaster protection and prevents data loss

By maintaining transactionally consistent copies of primary database

Protects against disasters, data corruption and user errors

Does not require expensive and complex HW/SW mirroring


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Data Guard and Remote Mirroring

Oracle Data Guards integrated disaster recovery solution

involving standby databases is often preferred to remote

disk mirroring

Better network efficiency

Better resilience and data protection

Higher ROI (backup, reporting servers, etc)

Remote mirroring (ie. HP Continuous Access) can be used

in combination with standby databases to protect non-database data


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Why Oracle Data Guard?

1. Disaster Recovery & High Availability Easy failover/switchover between primary and standby databases

2. Complete data protection Guaranteed zero data loss, safeguard against data corruptions

3. Efficient utilization of system resources Standby databases can be used for reporting, backups, queries

4. Balance data availability against performance Flexible data protection/synchronization modes

6. Centralized and simple management Push-button graphical interface for management and monitoring

5. Automatic resynchronization after restoration of network connectivity Automatic archive gap detection and resolution with no manual intervention

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