Oracle 10g Clusterware (CRS) Overview

18 Aug 2005 John Sheaffer Platform Solution Specialist john.sheaffer@oracle.com

Topics

    What is the Oracle Clusterware Clusterware components – – – Daemons VIP OCR & Voting Files Managing the Oracle Clusterware Q&A

Key Software Components

Server 1 Listener Oracle RAC ClusterWare OS Server 2 Listener Oracle RAC ClusterWare OS Server 3 Listener Oracle RAC ClusterWare OS

• • •

Server N Listener Oracle RAC ClusterWare OS Raw / CFS / NAS / ASM

What is the Oracle Clusterware?

 Oracle’s cluster manager layer for 10g + – – – – – Provides Cluster Management Services Provides High Availability Services Incorporates clustering technology licensed from True64 True Clusters No additional cost – supplied with 10g Database Same implementation on all platforms – Eliminates the need for 3 rd integration, and support party clusterware cost,

Clusterware Components

    crsd – Cluster Resource Services Daemon cssd – Cluster Synchronization Services Daemon evmd – Event Manager Daemon oprocd / hangcheck_timer – Node hang detector    VIP – Virtual IP OCR – Oracle Cluster Repository Voting Disk – Establishes quorum

Clusterware Components

  GSD – Global Services Daemon ONS – Oracle Notification Services Daemon

crsd – CRS Daemon

   Monitors the resources cluster that are part of the – Resource can be:  Listener     VIP ASM Instance Database Instance AWM Service Starts/Stops/Checks/Fails-over resources Maintains config information in the OCR

cssd – CSS Daemon

  Provides Group Services to the cluster – Tracks who is part of the cluster – Notifies CRS, RAC, and other cssds when nodes join/leave cluster Provides CRS locking services – – Locking w/in clusterware to coordinate actions across the cluster Entirely separate from Cache Fusion locking  Basically, CSS is the “Node Monitor”

evmd – Event Manager Daemon

 Provides an event-based messaging channel between crsd, cssd, and other processes  Can be extended with custom event handler scripts which evmd executes upon receipt of an event – Example:  Node down  send e-mail alert  Node down  log a trouble ticket

VIP – Virtual IP

 Each server has: – – Static IP VIP racnode1 (145.1.1.

101 ) racnode1-vip (145.1.1.

201 )  Clients always use the VIP  VIP allows rapid detection of server failures

VIP Failover

mydb = x.x.x.201

x.x.x.202

(Static) x.x.x.101

(VIP) x.x.x.201

(VIP) x.x.x.202

(Static) x.x.x.102

VIP Failover

mydb = x.x.x.201

x.x.x.202

(Static) x.x.x.101

TCP Reset (VIP) x.x.x.202

(VIP) x.x.x.201

(Static) x.x.x.102

VIP Failover

mydb = x.x.x.201

x.x.x.202

(Static) x.x.x.101

(VIP) x.x.x.202

(VIP) x.x.x.201

(Static) x.x.x.102

OCR & Voting Disks

  Oracle Cluster Repository (OCR) – Binary file containing a database (state directory) of CRS configuration & status information – – Maintained by the CRS Daemon Can be mirrored on 10g R2 Voting Disk – – Used by CSS to resolve split-brain scenarios Can be 1 or 3 files in 10g R2   These files must be outside of ASM Can be either raw partitions or regular files

Querying CRS status

[oracle]$ $CRS_HOME/bin/crs_stat NAME=ora.

linux1.vip

TYPE=application TARGET=ONLINE STATE= ONLINE on linux1 NAME=ora.

linux1.ASM1

.asm

TYPE=application TARGET=ONLINE STATE= ONLINE on linux1 NAME=ora.

linux2.vip

TYPE=application TARGET=ONLINE STATE= ONLINE on linux1   NAME=ora.

linux2.ASM2

.asm

TYPE=application TARGET=ONLINE STATE= OFFLINE on linux2 NAME=ora.ract.

mydb1.inst

TYPE=application TARGET=ONLINE STATE= ONLINE on linux1 NAME=ora.ract.

mydb2.inst

TYPE=application TARGET=ONLINE STATE= OFFLINE on linux2

...

Starting / Stopping CRS

 

/etc/init.d/init.crs start /etc/init.d/init.crs stop

 

/etc/init.d/init.crs disable /etc/init.d/init.crs enable

Starting / Stopping Resources

 

[oracle]$ srvctl stop database –d mydb

– Stops all RAC instances

[root]# srvctl stop nodeapps –n racnode1

– Stops Listener, VIP, GSD, ONS  

[oracle]$ srvctl start asm –n racnode1

– Starts ASM on racnode1 and all required dependencies

[oracle]$ srvctl start instance –d mydb –i mydb1

– Starts one instance and all required dependencies

Q U E S T I O N S A N S W E R S

Thank You

john.sheaffer@oracle.com