Oracle 10g Clusterware (CRS) Overview 18 Aug 2005 John Sheaffer Platform Solution Specialist

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

Server 1 Server 2 Server N ClusterWareClusterWare ClusterWare Key Software Components Server 3 ClusterWare OSOSOSOS Raw / CFS / NAS / ASM Oracle RAC Listener Oracle RAC Listener Oracle RAC Listener Oracle RAC Listener

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 party clusterware cost, integration, and support

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 that are part of the cluster – 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 alert  Node down  log a trouble ticket

VIP – Virtual IP  Each server has: – Static IPracnode1 ( ) – VIPracnode1-vip( )  Clients always use the VIP  VIP allows rapid detection of server failures

VIP Failover (Static) x.x.x.101 (Static) x.x.x.102 (VIP) x.x.x.201 (VIP) x.x.x.202 mydb = x.x.x.201 x.x.x.202

VIP Failover (Static) x.x.x.101 (Static) x.x.x.102 (VIP) x.x.x.201 (VIP) x.x.x.202 TCP Reset mydb = x.x.x.201 x.x.x.202

VIP Failover (Static) x.x.x.101 (Static) x.x.x.102 (VIP) x.x.x.201 (VIP) x.x.x.202 mydb = x.x.x.201 x.x.x.202

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

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

Thank You