Donna C. Hamby Sr. Principal Instructor Oracle University Oracle Corporation.

Donna C. HambySr. Principal InstructorOracle UniversityOracle Corporation

Oracle9i Real Application Clusters

What Is a Cluster?

– Interconnectednodes

– Cluster software hides thestructure

– Disks availablefor read andwrite by nodeor nodesrequiring the data theycontain

Node

Disks

Interconnect

What Is Oracle9i Real Application Clusters?– Database with

instances onseparate nodes

– Physical orlogical accessto each database file

– Software controls access todata

Database files

Instance on each node

Cluster Hardware Components

– Nodes– Interconnect– Shared disk subsystem

Interprocess Communication Software

– Is the second main subcomponent of the OSD clusterware

– Controls messages across the interconnect

– Transfers messages and data blocks for Real Application Clusters

OSDClusterware

ClusterManager

Nodemonitor

IPC

OSDClusterware

ClusterManager

Nodemonitor

IPC

Disk Access

Shared disk access is required for

– Control files– Data files– Online redo log

files– A quorum (or

voting) disk on some systems

– Configuration data– Optionally, a

server parameter file (SPFILE)

Instance

OSDClusterware

Connectionsto othernodes

Disk Access

Optional features requiring shared disk access include:

– Configuration information for management tools

– Server parameter file

– Separate undo tablespace for each instance if using automatic undo management

Connectionsto othernodes

Instance

OSDClusterware

Global Services Daemon

– Coordinates with other utilities and tools to manage Real Application Clusters databases and instances

– One GSD supports all databases on a node

– Requires no configuration

OSDClusterware

Instance

GSD

Background Processes

Additional background processes for a Real Application Clusters database consist of

– LMON– LMD– LMSn– LCK– DIAG

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

Global Enqueue Service Monitor

– Monitors global enqueues and resources across the cluster

– Performs recovery operations for cluster enqueues

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

Global Enqueue Service Daemon

– Manages access to global enqueues and resources

– Handles resource requests from other instances

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

Global Cache Service Processes

– Manage access to data blocks across the cluster

– Ship block images between the buffer caches of different instances (Cache Fusion)

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

LCK Process– Assists LMSn

processes with requests for resources between instances

– Handles cache resource request that do not involve Cache Fusion: dictionary and row cache

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

Diagnosability Daemon

– Captures diagnostic information related to instance process failures

– Logs information to the directory specified by BACKGROUND_DUMP_DEST

– Process cannot be configured and should not be stopped

InstanceLMS0LMON

LCK

LMD

DIAG

OSDClusterware

GSD Management– Start a GSD on all the

nodes in your Real Applications Clusters database for use by the management tools includingSRVCTLthe DBCAOEM

– Run only one GSD on each node

gsdservice -install

gsdservice -start

gsdservice -remove

gsd

Successfully started the daemon on the local node.

UNIX

Windows

Server Control Utility The Server Control Utility

(SRVCTL) – Is the preferred tool to

administer your Real Application Clusters database environment

– Manages cluster database configuration information used by several Oracle tools

– Provides cluster database management commands

– Requires the GSD to be running

Node 2

GSD

SRVCTL

Agent

Node 1

GSD

SRVCTL

Agent

SRVCTL Command Syntax

srvctl

Usage: srvctl {start|stop|status|config|add|delete|rename|move|get|set|unset} [options]

srvctl config -h

Usage: srvctl config [-p <db_name> [-n <node>]][-D <dbglvl>] [-h] [-V] -p <db_name> Show configuration for specified cluster database . . . -n <node> Only show services on named node -D <debuglvl> Debug level -h Print usage -V Show version

SRVCTL Cluster DatabaseConfiguration Tasks Modify database configuration

information– Add and delete cluster databases – Add instances to and delete instances from a

cluster database– Rename instances – Move instances– Set and unset the environment for an entire

cluster database– Set and unset instance environments

Add and Delete Databases Add database configuration information

Remove database configuration information

srvctl add db –p T2 –o $ORACLE_HOME

srvctl delete db –p T1

Add and Delete Instances

Add instance configuration information

Remove instance configuration information

srvctl add instance –p T2 –i T2N3 –n raclust3

srvctl delete instance –p T2 –i T2N1

Move and Rename Instances Move instance to new node in the static

configuration

Rename instance in the repository

srvctl move instance -p T2 -i T2N2 -n raclust1

srvctl rename instance -p T2 -i T2N2 -e T2N1

Store and Remove Environment Data

Store database-wide environment setting

Store instance-specific environment setting

Remove environment setting from single instance

srvctl set env -p T2 -t LANG=gb -i T2N1

srvctl set env -p T2 -t LANG=us

srvctl unset env -p T2 -t LANG -i T2N3

SRVCTL Cluster Database Tasks Manage cluster database components

– Start cluster databases and instances– Stop cluster databases and instances– Start and stop listeners associated with a

cluster database– Start and stop listeners associated with a

cluster database instance– Obtain the status of a cluster database

instance

Starting Databases and Instances

Start all instances and listeners

Start two named instances with their listeners

Start listener only on one node

srvctl start -p T2 –i T2N1,T2N2

srvctl start -p T2

srvctl start –p T2 –n raclust3 –s lsnr

Starting Databases and Instances Start all instances with nondefault

connect string

Start listeners and open instances with special parameter file on two nodessrvctl start -p T2 –n raclust1,raclust2 \ –o pfile=/ora/admin/initADMIN.ora

srvctl start -p T2 –c 'admin/adm1n as sysdba'

Stopping Databases and Instances Stop an instance only, not the listener

Shut down instances and listeners on three nodes using a nondefault connect stringsrvctl stop -p T2 \–n raclust2,raclust3,raclust4 \–c admin/adm1n as sysdba

srvctl stop –p T2 –i T2N3 –x lsnr

SRVCTL Cluster Database Tasks Manage cluster database components

– Start cluster databases and instances– Stop cluster databases and instances– Start and stop listeners associated with a

cluster database– Start and stop listeners associated with a

cluster database instance– Obtain the status of a cluster database

instance

Starting Databases and Instances

Start all instances and listeners

Start two named instances with their listeners

Start listener only on one nodesrvctl start -p T2 –i T2N1,T2N2

srvctl start -p T2

srvctl start –p T2 –n raclust3 –s lsnr

Starting Databases and Instances Start all instances with nondefault

connect string

Start listeners and open instances with special parameter file on two nodessrvctl start -p T2 –n raclust1,raclust2 \ –o pfile=/ora/admin/initADMIN.ora

srvctl start -p T2 –c 'admin/adm1n as sysdba'

Stopping Databases and Instances Stop an instance only, not the listener

Shut down instances and listeners on three nodes using a nondefault connect stringsrvctl stop -p T2 \–n raclust2,raclust3,raclust4 \–c admin/adm1n as sysdba

srvctl stop –p T2 –i T2N3 –x lsnr

Inspect Status of Cluster Database

List the active instances

Show the status of two instances

Display the status of the listener on one nodesrvctl status -p T2 –i T2N1,T2N4 –s inst

srvctl status -p T2

srvctl status –p T2 –n raclust2 –s lsnr

Inspect Database Configuration Information

List the instances defined for a database

List environment information for a database

List environment information for an instancesrvctl get env -p T2

srvctl config -p T2

srvctl get env -p T2 –i T2N4

Cache Fusion.

• Cache Fusion helps provide transparent scalability in a Real Application Clusters database

• The algorithms enable transportation of block images between instances

• The algorithms enable transportation of block images between instances

• Cache Fusion services track the current location and status of resources

• Directory structures within the SGA of each instance store the resource information

Cache Fusion Block Transfers:Example OverviewInstance A

1008

Instance D

Resourcemaster

Instance C

Instance B

Example 1: Read with No Transfer

Instance D

Resourcemaster

Instance CRequest toobtain a shared resource on C

N

1

1008

Instance BInstance A


Instance D

Resourcemaster

Instance C

N

1

1008

Instance BInstance A

2 The request is granted and the requesting instance is informed

N–>S


Instance A

Instance D

Resourcemaster

Instance B

Instance C

S

Read request

1

3

2 1008


Instance A

Instance D

Resourcemaster

Instance B

Block imagedelivered

Instance C

S

10081

2

3

4

1008

Example 2: Read to Write Transfer

Instance A

Instance D

Resourcemaster

Request to obtain an exclusive resource on B

Instance C

S

1008

Instance B

N

1

1008


Instance A

Instance D

Resourcemaster

Instance C

Instruction to transferthe block to B for exclusive access

S

1008

Instance B

N

2

1

1008


Instance A

Instance D

Resourcemaster

Instance CBlock and resource status (including C’s plan to close its resource)

S–>N

1008

Instance B

N

1008

2

1

3

1008


Resource assumptionand status messageInstance A

Instance D

Resourcemaster

Instance C

N

1008

Instance B

N–>X

1009

2

1

3

4

1008

Example 3: Write to Write Transfer

Instance D

Resourcemaster

Instance C

Instance A

N

Instance B

X

1009

Request to obtain resource inexclusive mode

1

1008


Instance C

Instance A

N

Instance B

X

1009

Instruction to transferexclusive resource to B

1

2

Instance D

Resourcemaster

1008


Instance D

Resourcemaster

Instance C

Instance B

X–>N

1009

Instance A

N

1009

Exclusive-keep copy of buffer

1

2

3

1008


Instance D

Resourcemaster

Instance C

Instance A

N–>X

1013

Instance B

1009

N

1

2

3

4

1008

Example 4: Write to Read Transfer

Instance A

Instance D

Resourcemaster

X

1013

Instance B

1009

N

Instance C

NRequest to obtainresource in shared mode 1

1008


Instance D

Resourcemaster

Instance A

X

1013

Instance B

1009

N

Instance C

NInstruction to transfer shared resource to C

1

2

1008


Instance D

Resourcemaster

Instance A

X–>S

1013

Instance B

1009

N

Instance C

N

1013

Shared-keep copy of buffer

3

2

1

1008


Instance D

Resourcemaster

Instance A

S

1013

Instance B

1009

N

Resource assumptioninformation

Instance C

N–>S

1013

2

3

4

1

1008

Block Transfers in Real Application Clusters

InstanceA

Node 1

InstanceB

Node 2

Cache Fusion block transfer

Block transfer with forced disk write

Notes on Using Multiblock Locks Use only for query intensive or

already-partitioned databases GC_FILES_TO_LOCKS -Assign the same

value to for every instance in a cluster database

Leave no white space in the parameter value between the double quotes: separate the entries for each set of file IDs with a colon

Notes on Using Multiblock Locks Configure Cache Fusion, instead of

multiblock locks, for selected files by– Not including their IDs in

GC_FILES_TO_LOCKS– Setting their LOCK_COUNT to zero and

not assigning a grouping factor

Real Application Clusters Guard Architecture

Monitors

VendorCMS

IP addresses

Listeners

Oracle instance

DGM

Application ormiddleware

Monitors

VendorCMS

IP addresses

Listeners

Oracle instance

DGM

IP (A) IP (B)

NodeB

(Secondary)

NodeA

(Primary)

Pack Pack

Disk group manager, only needed on some platforms

Real Application Clusters Guard Failover

VendorCMS

IP addresses

Listeners

Oracle instance

DGM

Monitors

VendorCMS

IP addresses

Listeners

Oracle instance

DGM

Heartbeat monitor

Listener monitor

Instance monitor

NodeA

NodeB

(New primary)

Pack Pack

Application ormiddleware

IP (A) IP (B)

Failover

Monitors

Listeners

Multiple listeners enable

– Client load balancing– Connect-time

failover– Transparent

Application Failover (TAF)

Clients Cluster nodes

Listeners

TNS Connect Descriptorsrac1= (DESCRIPTION= (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme1) (PORT=1630)) (CONNECT_DATA= (SERVICE_NAME=rac.us.aaacme.com)))

$ sqlplus qualassur1@rac1SQL*Plus: – Production(c) Copyright 2000 Oracle Corporation. All rights reserved.Enter password:

Host-Based Failover

Detect failure by monitoring the heartbeat Reorganize cluster membership in the

Cluster Manager Transfer disk ownership from the primary

node to a secondary node Restart application and database binaries Perform application and database recovery Reestablish client connections to the

failover node

Real Application Clusters Failover Detect failure by monitoring the

heartbeat Reorganize instance membership Perform instance recovery Reestablish failed client connections

TAF in Real Application Clusters Can be used with spare nodes or with

primary/secondary instance configurations

Designed for this environment, but can be used for

– Real Application Clusters Guard– Replicated systems– Data Guard

TAF Failover Mode Options

Must add failover options manually to TNS configuration files

They are part of the CONNECT_DATA section of a connect descriptor

TAF Failover Mode Options Failover options include

– TYPE: Identify the nature of TAF, if any– METHOD: Configure how quickly failover

can occur– BACKUP: Identify an alternate net service

name– RETRIES: Limit the number of times a

reconnection will be attempted– DELAY: Specify how long to wait between

reconnection attempts

TAF Implementation

The recommended configurations for TAF include:

– Connect-time failover with client load balancing

– Retrying connections– Pre-establishing connections

Connect-Time Failover with Client Load Balancingrac.us.aaacme.com=

(DESCRIPTION= (LOAD_BALANCE=on) (FAILOVER=on) (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme1) (PORT=1521)) (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme2) (PORT=1521)) (CONNECT_DATA= (SERVICE_NAME=rac.us.aaacme.com) (FAILOVER_MODE= (TYPE=select)(METHOD=basic))))

Retrying Failover Connections

rac1= (DESCRIPTION= (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme1) (PORT=1521)) (CONNECT_DATA= (SERVICE_NAME=rac1.us.aaacme.com) (FAILOVER_MODE= (TYPE=select)(METHOD=basic) (BACKUP=rac2) (RETRIES=20) (DELAY=15))))

rac2= (DESCRIPTION= . . .

Preestablishing a Connection for TAF

rac1= (DESCRIPTION= (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme1) (PORT=1521)) (CONNECT_DATA= (SERVICE_NAME= rac.us.acme.com) (INSTANCE_NAME=rac1) (FAILOVER_MODE= (BACKUP=rac2) (TYPE=select) (METHOD=preconnect))))

rac2= (DESCRIPTION= (ADDRESS= (PROTOCOL=tcp) (HOST=aaacme2) (PORT=1521)) (CONNECT_DATA= (SERVICE_NAME= rac.us.acme.com) (INSTANCE_NAME=rac2) (FAILOVER_MODE= (BACKUP=rac1) (TYPE=select) (METHOD=preconnect))))

AQ&Q U E S T I O N SQ U E S T I O N SA N S W E R SA N S W E R S

Donna C. Hamby Sr. Principal Instructor Oracle University Oracle Corporation.

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