In Enterprise Manager Grid Control 11g, changes in the Oracle Management Server JVM memory settings could be done in a file called startEMServer.sh located in a domain subdirectory like /u00/app/oracle/product/gc_inst/user_projects/domains/GCDomain/bin/.
And after an OMS restart, the JVM has used this new settings for the OMS. Since 12c, it can be done by an emctl command.
emctl – Get your actual Settings OMS_HEAP_MAX
oracle@solothurn:~/ [oms13cr1] emctl get property -name OMS_HEAP_MAX Oracle Enterprise Manager Cloud Control 13c Release 1 Copyright (c) 1996, 2015 Oracle Corporation. All rights reserved. SYSMAN password: Value for property OMS_HEAP_MAX for oms local_oms is 1740M
emctl – Change the Value
For example, the Memory will be resized to 2304M.
oracle@solothurn:~/ [oms13cr1] emctl set property -name OMS_HEAP_MAX -value 2304M Oracle Enterprise Manager Cloud Control 13c Release 1 Copyright (c) 1996, 2015 Oracle Corporation. All rights reserved. SYSMAN password: Property OMS_HEAP_MAX for oms solothurn.trivadistraining.com:4889_Management_Service has been set to value 2304M OMS restart is required to reflect the new property value
Verification
Restart your Oracle Management Server. In one of my tests this did not work. The OMS still used the old memory value. Another start/stop with emctl stop oms -all has worked.
oracle@solothurn:~/ [oms13cr1] emctl stop oms oracle@solothurn:~/ [oms13cr1] emctl start oms
The new value is now active:
oracle@solothurn:~/ [oms13cr1] emctl get property -name OMS_HEAP_MAX Oracle Enterprise Manager Cloud Control 13c Release 1 Copyright (c) 1996, 2015 Oracle Corporation. All rights reserved. SYSMAN password: Value for property OMS_HEAP_MAX for oms local_oms is 2304M
In Linux, you can search for the java process with ps -ef | grep “java -server -Xms256M -Xmx” – here are the first lines from my output where the Xmx parameter is located:
oracle 110597 110541 99 14:30 ? 00:04:50 /u00/app/oracle/product/em13cr1/oracle_common/jdk/bin/java -server -Xms256M -Xmx2304M -XX:PermSize=128M -XX:MaxPermSize=768M -XX:CompileThreshold=8000 -XX:-DoEscapeAnalysis -XX:+UseCodeCacheFlushing -XX:ReservedCodeCacheSize=100M -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+CMSClassUnloadingEnab
As you can see, the -Xmx Parameter is now set to 2304M, the Java virtual machine for EMGC_OMS1 is now using 2304M.