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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
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Agenda
• Introduction• High Availability
Concepts• High Availability
Challenges• High Availability
Solutions
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Agenda
• Oracle Advanced Replication
• Oracle Real Application Cluster (RAC)
• Oracle Data Guard
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Agenda
• Oracle Streams• Choose the Right
High-availability Solutions
• Summary• Q & A
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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)
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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High Availability Concepts
• 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.
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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High Availability Concepts
• 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%
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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High Availability Solutions
• High Availability Solution means :– No Single Points-of –failure– Hardware Redundancy– Software Redundancy– Data Redundancy– Application Redundancy
–More .. $ ?
– Save Money
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Oracle Advanced Replication
• Advanced Replication Overview
• Replication Components
• Types of Replication Environments
• Administration Tools for Replication
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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.
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Replication Components
• Replication Sites– Master Sites– Materialized View Sites
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Materialized View Replication
MaterializedView(read-only)
MasterTable(updatable)
MasterTable(updatable)
MasterTable(updatable)
MaterializedView(writeable)
MaterializedView(updatable)
Refresh
Update
Refresh
Refresh
Query
Update
Update
Update
Update
Application
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Replication Administration Tools
• Oracle Enterprise Manager– Replication Manager
• Oracle-Supplied PL/SQL packages– DBMS_REPCAT
• Replication Catalog– On every master sites – Materialized view sites
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Oracle Real Application Clusters (RAC)
• Real Application Clusters Overview
• Real Application Clusters Architecture
• Real Application Clusters Components
• Cache Fusion
• Transparent Application Failover (TAF)
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Option 2 (RAC)Option 1
Instance A
DB1
Instance BInstance AInstance B
DB1DB3
interconnect
Real Application Clusters Architecture
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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)
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Oracle Data Guard
• Data Guard History
• Data Guard Components
• Data Guard Roles
• Data Guard Interfaces
• Data Guard Process Architecture
• Data Guard Protection Mode
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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PrimaryDatabase
LogTransportServices
LogApply
ServicesO
racle Net
DataGuardBroker
DataGuardBroker
CLI GUI
StandbyDatabase
OnlineRedoLogs
LocalArchived
Logs
RemoteArchived
Logs
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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>
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Oracle Streams
• Oracle Streams Overview
• Oracle Streams Process Architecture
• Oracle Streams Rules
• Administration Tools for Oracle Streams
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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.
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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.
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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SourceDatabase
RedoLog
Capture ApplyDequeue
Propagate
TargetDatabase
Source Queue
LCRLCRUserMessageUserMessageLCRLCR......
Target Queue
LCRLCRUserMessageUserMessageLCRLCR......
Enqueue
Oracle Streams Processes Architecture
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Choose High-Availability Solution
• Product Licensing
• Unsupported Datatype
• Feature Comparison
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Product Licensing
High Availability Product Enterprise Edition
Advanced Replication Included
Real Application Clusters Additional License Fee
Data Guard Included
Streams Included
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Feature ComparisonAdvanced Replication
RAC Physical Standby
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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Feature Comparison
Advanced Replication
RAC Physical Standby
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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Feature Comparison
Advanced Replication
RAC Physical Standby
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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Feature Comparison
Advanced Replication
RAC Physical Standby
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
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Summary
• High Availability Concept
• High Availability Options– Advanced Replication– Real Application Clusters– Data Guard– Oracle Streams
• High Availability Product Comparison
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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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.
OracleWorld 2003, Paper #36693, Daniel T. Liu, FARES
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Thanks For Coming !!
Daniel Liu Contact Information
Phone: (714) 701-3346
Email: [email protected]
Email: [email protected]
Company Web Site:
http://www.firstam.com