How to change the number of OACORE JVMs in R12 with minimal disruption

Goal: To change the number of OACORE JVMs from 1 to 5 in R12 with almost no outage.

Highlights:

- No need to run autoconfig
- Minimal outage required (probaly < 1 min)
- Preserve the changes even if autoconfig is run at a later time.

Steps
1. On the Apache node, cd $ORA_CONFIG_HOME/10.1.3/opmn/conf/opmn.xml
2. Backup the opmn.xml
3. Edit the following section of opmn.xml


< /process-type>
< process-type id="oacore" module-id="OC4J" status="enabled" working-dir="$ORACLE_HOME/j2ee/home">
< module-data>
< category id="start-parameters">
< data id="java-options" value="-server -verbose:gc –Xmx1024M –Xms1024M -XX:MaxPermSize=160M -XX:NewRatio=2 -XX:+PrintGCTimeStamps -XX:+UseTLAB -XX:+UseParallelGC -XX:ParallelGCThreads=2 -Dcom.sun.management.jmxremote -Djava.security.policy=$ORACLE_HOME/j2ee/oacore/config/java2.policy -Djava.awt.headless=true -Dhttp.webdir.enable=false -Doracle.security.jazn.config=/apps/local/CEPRD/inst/apps/CEPRD_c7-ipnt-53/ora/10.1.3/j2ee/oacore/config/jazn.xml">
< data id="java-bin" value="/apps/local/CEPRD/inst/apps/CEPRD_c7-ipnt-53/admin/scripts/java.sh">
< data id="oc4j-options" value="-out /apps/local/CEPRD/inst/apps/CEPRD_c7-ipnt-53/logs/ora/10.1.3/opmn/oacorestd.out -err /apps/local/CEPRD/inst/apps/CEPRD_c7-ipnt-53/logs/ora/10.1.3/opmn/oacorestd.err">
< /category>
< category id="stop-parameters">
< data id="java-options" value="-server -verbose:gc -Xmx512M -Xms128M -XX:MaxPermSize=160M -XX:NewRatio=2 -XX:+PrintGCTimeStamps -XX:+UseTLAB -XX:+UseParallelGC -XX:ParallelGCThreads=2 -Djava.security.policy=$ORACLE_HOME/j2ee/oacore/config/java2.policy -Djava.awt.headless=true -Dhttp.webdir.enable=false">
< /category>
< category id="security-parameters">
< data id="wallet-file" value="file:/apps/local/CEPRD/inst/apps/CEPRD_c7-ipnt-53/certs/Apache">
< /category>
< /module-data>
< start retry="2" timeout="600">
< stop timeout="120">
< restart retry="2" timeout="720">
< port id="default-web-site" protocol="ajp" range="21585-21589">
< port id="rmi" range="20085-20089">
< port id="jms" range="23085-23089">
< process-set id="default_group" numprocs="1">
< /process-type>


In the above block, change the tag from < process-set id="default_group" numprocs="1">to < process-set id="default_group" numprocs="5">.

4. In the context file, change the following block from < oacore_nprocs oa_var="s_oacore_nprocs">1 to < oacore_nprocs oa_var="s_oacore_nprocs">5

5. Do NOT run autoconfig
6. adopmnctl.sh reload
7. Validate that 5 JVMs have been indeed started by adopmnctl.sh status

Risks and things to watch out for:

1. Make sure the port range for rmi and jms is 5.
2. Make sure those ports are not in use by using netstat command.
3. If the port range is not specifying 5 ports, assign 5 ports as per the port pool value.

For eg, if your port pool is 17, then rmi range will be 20085 - 20089 and jms range will be 23085- 23089.

4. Make similar change in context file so that your changes are not
5. You have a choice of customizing your template rather than directly changing your xml file as well.

- Aravind Kamath Posral