Presentation #36693 Presentation #36693 Oracle High Availability Solutions in a Nutshell Daniel T....

Presentation #36693Presentation #36693Oracle High Availability Solutions in a Nutshell

Daniel T. LiuSenior Technical Consultant

First American Real Estate Solutions

Date: Tuesday, September 10, 2003 @ 8:30 AM - 9:30 AM

Place: Moscone Room 104

OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES

2

Agenda

• Introduction• High Availability

Concepts• High Availability

Challenges• High Availability

Solutions


3

Agenda

• Oracle Advanced Replication

• Oracle Real Application Cluster (RAC)

• Oracle Data Guard


4

Agenda

• Oracle Streams• Choose the Right

High-availability Solutions

• Summary• Q & A


5

Introduction

• Why do we need to provide system and database High Availability?

• Planned Downtime– Database backup/upgrade/patching– Operating system upgrade/patching– Hardware and Network maintenance

• Unplanned Downtime– Corruptions

• Logical corruptions• Physical corruptions


6

Introduction

• Unplanned Downtime– Human Errors

• Accidentally drops, truncates a table• Accidentally delete, update rows in a table• Accidentally delete a data file or drop a

tablespace

– Disasters• War, terrorism• Earthquake, flood, fire or hurricane• No power for a long period• Server crash, malfunction of hardware


7

High Availability Concepts

• What is High Availability?– In the old days

• Local time

• Monday thru Friday

• 8 am to 6 pm

– Current environment• Global

• 365 x 24 x 7

• Minimal downtime (planned or unplanned)


8


• Understanding High Availability– Computing environments configured to provide

nearly full-time availability are known as high availability systems.

– When failures occur, the failover process moves processing performed by the failed component to the backup component.

– The more transparent that failover is to users, the higher the availability of the system.


9


• Measuring Availability– The mean time to recover (MTTR)– The mean time between failures (MTBF)– Total uptime in a year (%)

Minutes of Downtime

5 60 1440 2880

Minutes of Uptime

525595 525540 524160 522720

Minutes in a Year 525600 525600 525600 525600

Total Uptime in a Year (%)

99.9990% 99.9886% 99.7260% 99.4521%


10

High Availability Challenges

• Challenges for Database High Availability– Database size is getting bigger and bigger– Database Backup Time

• A DLT tape writes 6 MB/Second, or 21 GB/hour

• A 2 TB database with one tape driver will take 97 hours to backup

– Database Recovery Time– Is the backup good?– Trouble shooting time


11

High Availability Solutions

• Traditional High Availability Solutions– Backup and restore

• High Availability Solutions– Oracle Advanced Replication– Oracle Real Application Clusters (RAC)– Oracle Data Guard (Standby Database)– Oracle Streams


12

High Availability Solutions

• High Availability Solution means :– No Single Points-of –failure– Hardware Redundancy– Software Redundancy– Data Redundancy– Application Redundancy

–More .. $ ?

– Save Money


13

Oracle Advanced Replication

• Advanced Replication Overview

• Replication Components

• Types of Replication Environments

• Administration Tools for Replication


14

Advanced Replication Overview

• Replication is the process of copying and maintaining database objects, such as tables, in multiple database .

• Changes applied at one site are captured and stored locally before being forward and applied at each of the remote locations.


15

Replication Components

• Replication Objects– Table, Indexes, View

– Procedures, Packages, Functions, Triggers

– User-Defined Types

• Replication Groups– A collection of replication objects that are logically

related.

– Master group

– Materialized view group


16

Replication Components

• Replication Sites– Master Sites– Materialized View Sites


17

Types of Replication

• Multimaster Replication– Each master site operates as an equal peer.– Provides complete replicas of each replicated

table at each of the master sites.– Replicate changes for each transaction.– Two types of multimaster replication

• Asynchronous

• Synchronous


18

Asynchronous Data Replication

Destination Database

Destination Database

Source Database

Source Database

ReplicatedTable

ReplicatedTable

ReplicatedTable

ReplicatedTable

DeferredTransactionQueue

Change

Change

Trigger

Trigger

Remote ProcedureCall

Remote ProcedureCall

Procedure

Procedure

Synchronous Data Replication


19

Types of Replication

• Materialized View Replication– Replicate subset of master table data– Batch-oriented operation (refresh)– 3 types of materialized views

• Read-Only

• Updateable

• Writeable


20

Materialized View Replication

MaterializedView(read-only)

MasterTable(updatable)



MaterializedView(writeable)

MaterializedView(updatable)

Refresh

Update

Refresh

Refresh

Query

Update

Update

Update

Update

Application


21

Replication Administration Tools

• Oracle Enterprise Manager– Replication Manager

• Oracle-Supplied PL/SQL packages– DBMS_REPCAT

• Replication Catalog– On every master sites – Materialized view sites


22

Oracle Real Application Clusters (RAC)

• Real Application Clusters Overview

• Real Application Clusters Architecture

• Real Application Clusters Components

• Cache Fusion

• Transparent Application Failover (TAF)


23

Real Application Clusters Overview

• Multiple instances against the same database.

• Involves a cluster of nodes with access to a set of shared disks through Cluster Management Software (CMS).

• Oracle’s solution for system failures.• Transparent Application Failover (TAF)• Connection Load Balancing


24

Option 2 (RAC)Option 1

Instance A

DB1

Instance BInstance AInstance B

DB1DB3

interconnect

Real Application Clusters Architecture


25

Real Application Clusters Architecture

Node A

Instance A

Data FilesControl Files

Online Redo Files

Oracle SoftwareArchived Logs

Oracle SoftwareArchived Logs

LMSLMON LMD

SGA

GlobalResourceDirectory

Cluster GroupServices

VendorCMS

Node B

Instance B

LMSLMON LMD

SGA

GlobalResourceDirectory

Cluster GroupServices

VendorCMS

ClusterInterconnect

Local Disks Local DisksShared Disks


26

Real Application Clusters Components

• Shared Disk• Vendor CMS• Cluster Group Services• Global Resource Directory• RAC Background Process

– LMON (Global Cache Service Process)– LMD (Global Enqueue Service Daemon)– LMS (Global Enqueue Service Monitor)


27

Cache Fusion

• Oracle’s Global Cache Management Technology.

• It provides cache to cache transfers of data blocks between instances in a cluster.

• It eliminates forced disk writes.

• Dynamic resource re-mastering


28

Transparent Application Failover (TAF)

• Little or no user downtime.

• Applications and users are automatically and transparently reconnected to another system.

• DML transactions are rolled back


29

Oracle Data Guard

• Data Guard History

• Data Guard Components

• Data Guard Roles

• Data Guard Interfaces

• Data Guard Process Architecture

• Data Guard Protection Mode


30

Data Guard History

• History of Standby Database– Oracle7.3: First Release of Standby

Database– Oracle8i: Automatic shipping and

application of redo logs– Oracle9i Release 1: Protection mode– Oracle9i Release 2: Logical standby

database


31

Data Guard Components• Primary Database

• Standby Database– Physical Standby Database– Logical Standby Database (9iR2 only)

• Log Transport Services

• Network Configuration

• Log Apply Services

• Data Guard Broker


32

PrimaryDatabase

LogTransportServices

LogApply

ServicesO

racle Net

DataGuardBroker

DataGuardBroker

CLI GUI

StandbyDatabase

OnlineRedoLogs

LocalArchived

Logs

RemoteArchived

Logs


33

Data Guard Roles

A database can operate in one of the two mutually exclusive roles:

• Failover– One of the standby databases takes the

primary database role

• Switchover– In Oracle9i, primary and standby

database can continue to alternate roles


34

Data Guard Interface

• SQL*Plus and SQL StatementsSQL> alter database commit to switchover to physical standby;

• Data Guard Broker GUI– Data Guard Manager

• Data Guard Broker Command-Line Interface$ dgmgrlDGMGRL for Solaris: Version 9.2.0.1.0 - Production.

(c) Copyright 2002 Oracle Corporation. All rights reserved.

Welcome to DGMGRL, type "help" for information.DGMGRL>


35

Process Architecture

• Physical/Logical Standby Processes– LGWR (Log Writer) process– ARCH (Archiver) process– LNS (LGWR Network Server) process– RFS (Remote File Server) process– MRP (Managed Recovery) process


36

Process Architecture

• Physical/Logical Standby Processes– FAL (Fetch Archive Log) Client process– FAL (Fetch Archive Log) Server process– LSP (Logical Standby) process– PX (Parallel Execution) process– DMON (Data Guard Broker Monitor) process


37

Physical Standby Processes Architecture

PrimaryDatabase

Oracle N

et

LGWR LNS

FALServer

ARCH

FALClient/MRPARCH

DMON DMON

RFS

SYNC

ASYNC

Physicalstandby

Database

OnlineRedoLogs

LocalArchived

Logs

RemoteArchived

Logs

StandbyRedoLogs


38

Logical Standby Processes Architecture

PrimaryDatabase

Oracle N

et

LGWR LNS

ARCH

LSP0

DMON DMON

RFS

SYNC

ASYNC

LogicalStandbyDatabase

PX

PX

PX

PX

MiningGroup

ApplyingGroup

OnlineRedoLogs

LocalArchived

Logs

RemoteArchived

Logs


39

Data Protection Mode• Oracle9i Release 2 has three data protection modes

Mode Log Writing Process

Network Trans Mode

Disk Write Option

Redo Log Reception Option

Supported on

Maximum Protection

LGWR SYNC AFFIRM Standby redo logs are required

Physical standby databases

Maximum Availability

LGWR SYNC AFFIRM Standby redo logs

Physical and logical standby databases

Maximum Performance

LGWR or ARCH

SYNC or ASYNC

NOAFFIRM Standby redo logs

Physical and logical standby databases


40

Oracle Streams

• Oracle Streams Overview

• Oracle Streams Process Architecture

• Oracle Streams Rules

• Administration Tools for Oracle Streams


41

Oracle Streams Overview

• Oracle9i’s new replication product.• Similar to logical standby database• Changes are captured at source

Database.• Propagate information within a database

or from one database to another.• Using Message Queuing.• Heterogeneous information sharing.


42

Oracle Streams Process Architecture

• Capture changes at a database.

• Enqueue events into a queue.

• Propagate events from one queue to another.

• Dequeue events.

• Apply events at a database.


43

SourceDatabase

RedoLog

Capture ApplyDequeue

Propagate

TargetDatabase

Source Queue

LCRLCRUserMessageUserMessageLCRLCR......

Target Queue

LCRLCRUserMessageUserMessageLCRLCR......

Enqueue

Oracle Streams Processes Architecture


44

Oracle Streams Rules

• Rules are used to control which information to share and where to share it.

• Rules can be used during capture, propagate, and apply processes.

• Rules can define in three level:– Table

– Schema

– Global


45

Oracle Streams Administration Tools

• Oracle-Supplied PL/SQL packages– DBMS_STREAMS_ADM– DBMS_CAPTURE_ADM– DBMS_PROPAGATION_ADM– DBMS_APPLY_ADM

• Streams Data Dictionary views– DBA_APPLY– V$STREAMS_CAPTURE

• Oracle Enterprise Manager


46

Choose High-Availability Solution

• Product Licensing

• Unsupported Datatype

• Feature Comparison


47

Product Licensing

High Availability Product Enterprise Edition

Advanced Replication Included

Real Application Clusters Additional License Fee

Data Guard Included

Streams Included


48

Unsupported Datatype for Logical Standby and Streams

Supported Datatypes Unsupported Datatypes CHAR, NCHAR

VARCHAR2, NVARCHAR2

NUMBER

DATE

CLOB,BLOB

RAW

TIMESTAMP

TIMESTAMP WITH TIME ZONE

TIMESTAAMP WITH LOCAL TIME ZONE

INTERVAL YEAR TO MONTH

INTERVAL DAY TO SECOND

NCLOB

LONG

LONG RAW

BFILE

ROWID

UROWID

User-defined types

Object types

- REFS

- Varrays

- Nested tables


49

Feature Comparison

Advanced Replication

RAC Physical Standby

Logical Standby

Streams

Entire Database Replication

YES N/A YES YES YES

Schema Replication YES N/A NO NO YES

Table Replication YES N/A NO NO YES


50

Feature ComparisonAdvanced Replication


Logical Standby

Streams

DML Replication YES N/A YES YES YES

DDL Replication YES N/A YES YES YES

Instance Redundant YES YES YES YES YES

Database Redundant YES NO YES YES YES


51

Feature Comparison



Logical Standby

Streams

Cluster Management Software

NO YES NO NO NO

Failover Mechanism

Manual Failover

TAF FailoverSwitchover

FailoverSwitchover

Manual Failover

Load Balancing YES YES

YES

PartialYES YES


52

Feature Comparison



Logical Standby

Streams

Change Captured Local Local Remote Remote Local

Heterogeneous Database Support

YES NO NO NO YES

Datatype Support ALL ALL SOME SOME SOME


53

Feature Comparison



Logical Standby

Streams

OS Platform between source and Target

Can be Different

Must be

Same

Must

be Same

Must

be Same

Can be Different

Oracle Version Between Source and Target

Can

be Different

Must be

Same

Must

be Same

Must

be Same

Can

be Different


54

Summary

• High Availability Concept

• High Availability Options– Advanced Replication– Real Application Clusters– Data Guard– Oracle Streams

• High Availability Product Comparison


55

ReferencesOracle9i, Data Guard Concepts and Administration. Release 1 (9.0.1);Oracle9i, Data Guard Concepts and Administration. Release 2 (9.2);Oracle9i, Data Guard Broker. Release 2 (9.2);Oracle9i, Real Application Clusters, Concepts. Release 1 (9.0.1);Oracle9i, Advanced Replication. Release 2 (9,2);Oracle9i, Streams. Release 2 (9.2); Oracle Metalink Support;Top DBA Shell Scripts for Monitoring Database, Daniel T. Liu; DBAZine;

I would also like to acknowledge the assistance of Larry Barry, Ann Collins, Archana Sharma and Husam Tomeh of FARES, and Larry Carpenter, Joseph Meeks, Roger Peterson of Oracle Corporation.


56

Thanks For Coming !!

Daniel Liu Contact Information

Phone: (714) 701-3346

Email: [email protected]

Email: [email protected]

Company Web Site:

http://www.firstam.com

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