RAC ADMINISTRATION COMMANDS

Its very helpful for everyone to understand the RAC ADMINISTRATION COMMANDS in Oracle database. RAC stands for Real Application Cluster which help to manage the high availability of database in case of any disaster. There are some useful command which are using in daily routine to stop and start the services of RAC.

Oracle Real Application Clusters

Oracle Real Application Clusters (RAC) allow to run a single standalone Oracle Database across multiple servers in order to maximize availability and enable horizontal scalability, while accessing shared storage. User sessions connecting to Oracle RAC instances can failover and safely replay changes during outages, without any changes to end user applications, hiding the impact of the outages from end users.

A cluster comprises multiple interconnected computers or servers that appear as if they are one server to end users and applications. Oracle RAC enables you to cluster an Oracle database. Oracle RAC uses Oracle Clusterware for the infrastructure to bind multiple servers so they operate as a single system.

RAC ADMINISTRATION COMMANDS

crs_stat -t                       Shows HA resource status (hard to read)

crsstat                           Ouptut of crs_stat -t formatted nicely

ps -ef|grep d.bin crsd.bin evmd.bin ocssd.bin

crsctl check crs CSS,CRS,EVM      appears healthy

crsctl stop crs                   Stop crs and all other services

crsctl disable crs*               Prevents CRS from starting on reboot

crsctl enable crs*                Enables CRS start on reboot

crs_stop -all                     Stops all registered resources

crs_start -all                    Starts all registered resources   

Database Administration Commands

srvctl start instance -d <db_name> -i <inst_name> Starts an instance

srvctl stop instance -d <db_name> -i <inst_name> Stops an instance

srvctl status instance -d <db_name> -i <inst_name> Checks an
individual instance

srvctl start database -d <db_name> Starts all instances

srvctl stop database -d <db_name> Stops all instances

srvctl status database -d <db_name> Checks status of all

srvctl start service -d <db_name> -s <service_name> Starts a service

srvctl stop service -d <db_name> -s <service_name> Stops a service

srvctl status service -d <db_name> Checks status of a service

srvctl start nodeapps -n <node_name> Starts gsd, vip, listener

srvctl stop nodeapps -n <node_name> Stops gsd, vip and listener

BACKGROUND PROCESSES INFORMATION

There are three main background processes you can see when doing a

ps –ef|grep d.bin. They are normally started by init during the

operating system boot process. They can be started and stopped

manually by issuing the command /etc/init.d/init.crs

{start|stop|enable|disable}

/etc/rc.d/init.d/init.evmd

/etc/rc.d/init.d/init.cssd

/etc/rc.d/init.d/init.crsd

SERVICES

When the above Background processes are running then these process start a no. of services assumes you are using ASM and TAF loadbalancing.

1. The nodeapps (gsd, VIP, ons, listener) are brought online.

2.The ASM instances are brought online.

3. The database instances are brought online.

4. Any defined services are brought online.

To Learn more about RAC Command go to Managing Cluster CRS

To find more details of RAC click on ORACLE-BASE

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