ORACLE DATABASE HIGH AVAILABILITY

&ORACLE 11GR2 DATA GUARD

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Güneş EROL

OUTLINE

I. Overview Of High AvailabilityII. Oracle Database High Availability ArchitectureIII. Determining Your High Availability Requirements

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OVERVIEW OF HIGH AVAILABILITY

What is Availability ? Availability is the degree to which an application,

service, or functionality is available upon user demand.

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Direct cost: lost productivity, lost revenue. Indirect cost: damaged customer

relationships, bad publicity, and lawsuits.

Importance Of High Availability• Support enterprises to gain their competitive

advantages by providing capability of continuously accessing to critical business data.

• Much downtime (surpass the threshold) can cause

OVERVIEW OF HIGH AVAILABILITY

MAIN ATTRİBUTES OF AVAILABILITY:

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Attribute Why Important

1. Redundancy with isolation No single point of failure, failures stay put

2. Zero data loss Complete protection, no recovery concerns

3. Extreme performance Deploy for any application

4. Automatic failover Fast, predictable

5. Full systems utilization Fast recovery, high return on investment

6. Management simplicity Reliable, reduced administrative costs

OVERVIEW OF HIGH AVAILABILITY

Causes Of Downtime Unplanned:

Computer failure Storage failure Human error Data corruption Site failure

Planned:

System changes Data changes 6

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ORACLE MAXIMUMAVAILABILITY ARCHITECTURE (MAA)

ORACLE MAXIMUMAVAILABILITY ARCHITECTURE (MAA)

Oracle Database 11g with Data Guard * Oracle Database 11g with RAC ** Oracle Database 11g with RAC and Data Guard – MAA ***

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ORACLE DATABASE 11G WITH DATA GUARD Data Guard provides a comprehensive set of

services that create, maintain, manage, and monitor one or more standby databases to enable Oracle databases to survive disasters, failures, errors and data corruption.

Two types of standby databases:• Physical standby database• Logical standby database

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Three type of Data Guard Protection Modes:

• Maximum Protection• Maximum Avaliablity• Maximum Performance

ORACLE DATABASE 11G WITH DATA GUARD

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ORACLE DATABASE 11G WITH DATA GUARD

• Physical standby database provide these advantages: Protection from user errors and logical

corruption Protection from disasters and site failures if

located remotely Standby database can diverge for reporting or

testing purposes and resynchronize with its primary database once complete

Backups can be taken from the physical standby database instead of the production database, relieving the load on the production database

Enable rolling database upgrades of the production database

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ORACLE DATABASE 11G WITH DATA GUARD

• Logical standby database provide these advantages: Logical Standby Database is an open,

independent, active database A logical standby database can be used for

other business purposes in addition to disaster recovery.

Users can access a logical standby database for queries and reporting purposes.

Not all Data Types supported(e.g., BFILE, Collections (including VARRAYS and nested tables), Encrypted columns)

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DATA GUARD PROTECTION MODES

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ORACLE DATABASE 11G WITH DATA GUARD SYNC&ASYNC

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ORACLE DATABASE 11G FEATURES The Active Data Guard option, first available with Oracle

Database 11g, Snapshot Standby A logical standby database has the additional flexibility of

being open read-write Heterogenous Platform Support

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ORACLE DATABASE 11G FEATURES The Active Data Guard option, first available with Oracle

Database 11g, enables a physical standby database to be open read-only while redo transport and standby apply are both active..

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ORACLE DATABASE 11G FEATURES Snapshot Standby enables a physical standby database to

be open read-write for any activity that requires a read-write replica of production data (e.g., testing).

A Snapshot Standby continues to receive, but not apply, redo generated by the primary. Redo is applied automatically when the Snapshot Standby is converted back to a physical standby database.

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ORACLE DATABASE 11G FEATURES A logical standby database has the additional flexibility of

being open read-write. While data maintained by SQL Apply cannot be modified, you can add additional local tables, create local index structures to optimize reporting, use the standby database as a data warehouse, or use it to transform information used to load data marts

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ORACLE DATABASE 11G WITH RAC This architecture provides the following

benefits:• Fast node (measured in minutes) and instance

failover (measured in seconds)• Rolling patch upgrades • Multiple active instance availability and

scalability across multiple nodes

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ORACLE DATABASE 11G WITH RAC Oracle Database 11g with RAC architecture

uses Real Application Clusters and is an inherently high availability system

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ORACLE DATABASE 11G WITH RAC AND DATA GUARD – MAA

• RAC and Data Guard provide the basis of Oracle Database 11g – Maximum Availability Architecture (MAA).

• Symmetric sites also enable processes and procedures to be kept the same between sites, making operational tasks easier to maintain and execute.

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ORACLE DATABASE 11G WITH RAC AND DATA GUARD – MAA

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DETERMINING YOUR HIGH AVAILABILITY REQUIREMENTS

Analysis Framework for Determining High Availability Requirements

• Business Impact Analysis• Cost of Downtime• Recovery Time Objective (RPO)• Recovery Point Objective (RTO)

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DETERMINING YOUR HIGH AVAILABILITY REQUIREMENTS

• Planning and Implementing a Highly Available Enterprise

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PERFORMANCE AND SCALABILITY

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500

1000

1500

2000

2500

3000

290

1,530

2,610

630

Tran

sact

ion

s / s

ec

All servicesrun on primary

database

Read-onlyoffloaded to

standby

Read-write service

Read-only service

+ 117%

+ 70%

More scalableBetter performance:- Eliminate contention between

read-write and read-only workload

- Simplify performance tuning

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PERFORMANCE AND SCALABILITY

+250% transactions per second on Primary+110% performance per second on Read process

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