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  4. Oracle Restart – new in 11g R2

Oracle Restart – new in 11g R2

Similar to the clusterware processes in a RAC environment, in 11g R2 even for a standalone instance, functionality is now available to automatically restart components like the database, listener, ASM diskgroup, service etc in the event of their failure.

This feature is called Oracle Restart and it runs out of the Grid Infrastructure home which is separate from the database home.

Oracle Restart is managed by CRSCTL utility and it uses Oracle High Availability Services to start and stop the components managed by Oracle Restart.

Using Oracle Restart, we can stop or start all the components running out of a single Oracle Home with a single srvctl command as well as Oracle Restart will automatically start all components on machine reboot in the proper order taking into account dependencies like ASM instance and the managed database instances. So no more do we have to use the dbstart and dbstop scripts to manage this.

Oracle Restart can be extended to Data Guard configurations as well by integrating with Data Guard Broker to manage the start and stop of database services following a data guard role transition.

Let us examine some of the srvctl commands which can be executed in a single instance environment as well as see the use of the crsctl command – normally previously only used for RAC environments.

-bash-3.2$ crs_stat -t
Name           Type           Target    State     Host
------------------------------------------------------------
ora.DATA1.dg   ora....up.type ONLINE    ONLINE    redhat64
ora....ER.lsnr ora....er.type ONLINE    ONLINE    redhat64
ora....WARE.dg ora....up.type ONLINE    ONLINE    redhat64
ora.asm        ora.asm.type   ONLINE    ONLINE    redhat64
ora.cssd       ora.cssd.type  ONLINE    ONLINE    redhat64
ora.diskmon    ora....on.type ONLINE    ONLINE    redhat64
ora.eons       ora.eons.type  ONLINE    ONLINE    redhat64
ora.ons        ora.ons.type   ONLINE    ONLINE    redhat64


bash-3.2$ ./crsctl check has
CRS-4638: Oracle High Availability Services is online

-bash-3.2$ ./crsctl check css
CRS-4529: Cluster Synchronization Services is online

-bash-3.2$ ./srvctl start listener

-bash-3.2$ ps -ef |grep tns
oracle   14899     1  0 14:08 ?        00:00:00 /u02/app/oracle/product/11.2.0/grid/bin/tnslsnr LISTENER -inherit

-bash-3.2$ ./srvctl status listener
Listener LISTENER is enabled
Listener LISTENER is running on node(s): redhat64

-bash-3.2$ ./srvctl status asm
ASM is running on redhat64

-bash-3.2$ ./srvctl status diskgroup -g DATA1
Disk Group DATA1 is running on redhat64

-bash-3.2$ ./srvctl config asm
ASM home: /u02/app/oracle/product/11.2.0/grid
ASM listener: LISTENER
Spfile: +DATA1/asm/asmparameterfile/registry.253.700932479
ASM diskgroup discovery string: /dev/raw/raw*

In case a process dies unexpectedly, Oracle Restart will automatically start the process. In the example below, we kill the PMON process of the ora11gr2 instance and find that in less than 5 seconds the instance has been restarted by the Oracle High Availablity Service running in the background constantly monitoring the health of the managed components.

-bash-3.2$ ps -ef |grep pmon
oracle   12710     1  0 Oct22 ?        00:00:01 asm_pmon_+ASM
oracle   15752     1  0 14:14 ?        00:00:00 ora_pmon_ora11gr2
oracle   15975 18271  0 14:15 pts/2    00:00:00 grep pmon

-bash-3.2$ kill -9  15752

-bash-3.2$ ps -ef |grep pmon
oracle   12710     1  0 Oct22 ?        00:00:01 asm_pmon_+ASM
oracle   16679     1  0 14:22 ?        00:00:00 ora_pmon_ora11gr2
oracle   16775 18271  0 14:22 pts/2    00:00:00 grep pmon

In this example we stop all the components running out of a particular home by executing the srvctl stop home command. After stopping the database home, we find that only the ASM instance is running as it is managed by a seperate home which is the Grid Infrastructure home. After the database home is started, the database instance ora11gr2 also is automatically started.

[oracle@redhat346 ~]$ srvctl stop home -o /u01/app/oracle/product/11.2.0/dbhome_1 -s /tmp/state

[oracle@redhat346 ~]$ ps -ef |grep pmon
oracle   19841     1  0 Sep18 ?        00:01:24 asm_pmon_+ASM
oracle   31843 27855  0 15:19 pts/1    00:00:00 grep pmon

[oracle@redhat346 ~]$ srvctl start home -o /u01/app/oracle/product/11.2.0/dbhome_1 -s /tmp/state

[oracle@redhat346 ~]$ ps -ef |grep pmon
oracle   19841     1  0 Sep18 ?        00:01:24 asm_pmon_+ASM
oracle   26690     1  0 Oct08 ?        00:00:41 ora_pmon_emrep
oracle   32054     1  0 15:20 ?        00:00:00 ora_pmon_testdb
oracle   32344     1  0 15:20 ?        00:00:00 ora_pmon_ora11gr2
oracle   32620 27855  0 15:22 pts/1    00:00:00 grep pmon
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Gavin Soorma

Latest posts by Gavin Soorma (see all)

Updated on June 2, 2021

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Comments

  1. Hi – can you specify in more detail what probems you are having and which all components are not starting after a machine reboot? – thanks

  2. I know this is a little old now so maybe someone is still watching.

    How do you make it shut the database down automatically when you do init 0 or init 6?

  3. Gavin, very good article on this new features of 11g R2. I was wondering why asm was starting automatically whenever I reboot my linux server but now I know why. Oracle has changed how it controls processes in 11gR2. Is there anyway to stop asm to stop starting on reboot? what is the command how can I find that asm is set to start automatic on reboot? Thank you.

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