10 grac service architecture

8/13/2019 10 Grac Service Architecture

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Oracle10g RAC ServiceArchitecture

Overview of Real Application ClusterReady Services, Nodeapps, and User

Defined Services


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Overview

Service Architecture

Cluster Ready Services (CRS)

Nodeapps

User defined Services

ASM Services

Internally Managed Services Monitoring Services


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RAC Service Architecture

Oracle 10g RAC features a service basedarchitecture

This is an improvement over 9i RAC in

several ways Increased flexibility

Increased manageability

Improvements in High Availability Enables 10g Grid Deployment


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RAC Services and HighAvailability

Oracle Services facilitate high availability ofdatabases and related applications

If key database resources become unavailable(network, storage, etc.): Instances and Services will be relocated to another

node

The failed node will be rebooted

By default, after any server boot-up, Oracle

attempts to restart all services on the node


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Cluster Ready Services

Manage the RAC Cluster Several Different Services

OracleCRSService

Oracle CSService

OracleEVMService OraFenceService

Required for RAC installation

Installed in its own CRS_HOME


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CRS Basics

Used to manage RAC Only one set of CRS Daemons per system

Multiple instances share the same CRS

CRS runs as both root and Oracle users CRS must be running before RAC can

start


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CRS Management

Started automatically Can stop and start manually

Start the OracleCRSService

Stop the OracleCRSService

Uses the voting disk and OCR (Oracle ClusterRepository)

Requires 3 network addresses Public

Private

Virtual Public


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CRS Services

OracleCRSService Cluster Ready Services Daemon

OracleCSService

Oracle Cluster Synchronization Service Daemon

OracleEVMService

Event Manager Daemon

OraFenceService

Process Monitor


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Cluster Ready Services DaemonOracleCRSService Runs as Administrator user Automatically restarted

Manages Application Resources

Starts, stops and fails-over application resources Maintains the OCR (Oracle Cluster Repository)

Keeps state information in the OCR


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Oracle Cluster Synchronization

Service DaemonOracleCSService Runs as Administrator user

Maintains the heartbeat (failure causes systemreboot)

Provides Node Membership

Group Access

Basic Cluster Locking

Can integrate with 3rdparty clustering productsor run standalone

OracleCSService also works with non-RACsystems


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Event Manager DaemonOracleEVMService Runs as Administrator user Restarts on failure

Generates Events

Starts the racgevt thread to invokes ServerCallouts


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Process MonitorOraFenceService Runs as Administrator user Locked in memory to monitor the cluster

Provides I/O fencing

OraFenceService periodically monitors clusterstatus, and can reboot the node if a problem isdetected

An OraFenceService failure results in Oracle

Clusterware restarting the node


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RACG

RACG is a behind-the-scenes process (orthread) that extends clusterware tosupport Oracle-specific requirements andcomplex resources.

Runs server callout scripts when FANevents occur.

Runs as processes (or threads), not as a

service (racgmain.exe, racgimon.exe)


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Cluster Ready ServicesManagement

Log Files

OracleCRSService

%ORA_CRS_HOME%\log\hostname\crsd

Oracle Cluster Registry (OCR)

%ORA_CRS_HOME%log\hostname\ocr

OracleEVMService

%ORA_CRS_HOME%\log\hostname\evmd

OracleCSService

%ORA_CRS_HOME%log\hostname\cssd

RACG

%ORA_CRS_HOME%log\hostname\racg


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Nodeapp Services

Nodeapps are a standard set of Oracleapplication services that are automaticallylaunched for RAC

Virtual IP (VIP)

Oracle Net Listener

Global Services Daemon (GSD)

Oracle Notification Service (ONS)

Nodeapp services run on each node

Can be relocated to other nodes through the virtual IP


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VIP (Virtual IP)

Creates a virtual IP address used by the Listener

The virtual IP address fails over between nodes

Multiple virtual IP addresses can exist on thesame system (during failover)

Independent of the Oracle Instance Potential Problem if more than one database per

node


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Global Services Daemon(GSD) The daemon which executes SRVCTL

commands

GSD receives requests from SRVCTL toexecute administrative tasks, such as startup orshutdown

The command is executed locally on eachnode, and the results are sent back toSRVCTL.

The daemon is installed on the nodes bydefault. It is important that you do not kill thisprocess and it should not be deleted.


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Listener

Server-side component of Oracle Net

Listens for incoming client connection requests

Manages the traffic to the server; when a clientrequests a network session with a server, the

listener actually receives the request andbrokers the client request

If the client's information matches the listener'sinformation, then the listener grants a connection

to the server.


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Oracle Notification Service(ONS)

The Oracle Notification Service isinstalled automatically on each RAC nodeas a Node Application

ONS starts automatically with each boot ONS uses a simple push/subscribe

method to publish event messages to all

RAC nodes with active ONS daemons


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ONS and Fast ApplicationNotification

ONS can be configured to run on nodeshosting client or mid-tier applications

ONS is the key component of Fast

Application Notification (FAN) Can be utilized to extend RAC high

availability and load balancing to mid-tierapplications

Independent of True Application Failover

Less reliance on network configuration


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User Defined Services

User defined, named services may be createdto manage database resources that areassociated with application workloads

One or more database instances may be

mapped to a single service A database instance may be assigned to one or

more services

The Automated Workload Repository may be

used to monitor Service metrics


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User Defined Services andFailover Services can be defined with preferred

and alternate instances

A service may be assigned to start on

preferred instances The same service may have alternate

instances assigned for failover

If multiple services are assigned for the same

database, the preferred and alternateinstance assignments may be different foreach service


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Automatic Storage ManagementServices Automatic Storage Management (ASM) is a

storage option for creating and managingdatabases

ASM operates like a Logical Volume Manager

between the physical storage and the database. A small, automatically managed Oracle database

instance is created on each node (if ASM is chosenas a storage option)

ASM instances start automatically as Oracleservices


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Internally Managed Services When the Global Services Daemon is started as a part

of the Node Applications, it in turn launches keyinternally managed services The Global Cache Service manages Cache Fusion and in-

memory data buffers

The Global Enqueue Service manages inter-instance lockingand RAC recovery

GCS and GES show up as OS processes or threads,but GSD is the only service that can be externallycontrolled

GCS and GES together manage a set of virtual tables

in memory, called the Global Resouce Directory


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Global Cache Service (GCS)

The controlling process that implements Cache Fusion.

Manages the status and transfer of data blocks across the buffercaches of all instances.

Tightly integrated with the buffer cache manager to enable fastlookup of resource information in the Global Resource Directory.

Maintains the block mode for blocks in the global role.

Employs various background processes (or threads) such as theGlobal Cache Service Processes (LMSn) and Global EnqueueService Daemon (LMD).


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Global Enqueue Service Monitor(LMON)

Background process that monitors theentire cluster to manage global resources.

Manages instance and process expirations

and recovery for GCS. Handles the part of recovery associated

with global resources


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Global Resource Directory

The data structures associated with global resources. Itis distributed across all instances in a cluster.

Global Cache Service and Global Enqueue Servicemaintain the Global Resource Directory to recordinformation about resources and enqueues held

globally. The Global Resource Directory resides in memory and

is distributed throughout the cluster to all nodes. In thisdistributed architecture, each node participates inmanaging global resources and manages a portion of

the Global Resource Directory.


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Monitoring RAC Services %ORA_CRS_HOME%\bin\crs_stat

NAME=ora.rac1.gsd TYPE=application

TARGET=ONLINE

STATE=ONLINE

NAME=ora.rac1.oem TYPE=application

TARGET=ONLINE

STATE=ONLINE

NAME=ora.rac1.ons

TYPE=application

TARGET=ONLINE

STATE=ONLINE

C S


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Monitoring RAC Services Creating a tabular report:

%ORA_CRS_HOME%\bin\crs_stat -tName Type Target State Host

--------------------------------------------------------------------------------------------------

ora.rac1.gsd application ONLINE ONLINErac1

ora.rac1.oem application ONLINE ONLINErac1

ora.rac1.ons application ONLINE ONLINErac1

ora.rac1.vip application ONLINE ONLINE rac1

ora.rac2.gsd application ONLINE ONLINE

rac2ora.rac2.oem application ONLINE ONLINE

rac2

ora.rac2.ons application ONLINE ONLINErac2

ora.rac2.vip application ONLINE ONLINE rac2

R i


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Review

What advantages does a service basedarchitecture offer?

What four services comprise ClusterReady Services?

Nodeapps consists of which fourapplications?

True or False: a database instance maybe assigned to multiple services


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Summary Service Architecture

Cluster Ready Services (CRS)

OracleCRSService

OracleCSService

OracleEVMService

OraFenceService

Nodeapps

VIP Listener

GSD

ONS

User defined Services

ASM Services

Internally managed services

Global Cache Service

Global Enqueue Service

Global Resource Directory

Monitoring Services

10 grac service architecture

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