Cannot start oms EM 12c

The OMS is failing to start and the problem seems to the the connectivity to the repository DB. I have observe that the connection to the DB from SQL Plus is failing. To check if the OMS is able to connect, perform the connectivity check using the rcuJDBCEngine.

1. Get the connection details by running the command
./emctl config oms -list_repos_details

2. Please refer to the following note for details on checking the connectivity from OMS to repository using rcuJDBCEngine.
12c Cloud Control: How to Verify the Connectivity from 12c OMS to Repository Database using rcuJDBCEngine (Doc ID 1448007.1)

Solution

1) stop any running processes using:-

$/bin/emctl stop oms -all -force

2) Check whether there are any remaining processes:-

ps -ef | grep EMGC_ADMINSERVER
ps -ef | grep EMGC_OMS1
ps -ef | grep java

kill any of the above processes which are running from the OMS $ORACLE_HOME using 'kill -9 '

3) Remove the *.DAT and *.lok files:

$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_OMS1/data/store/diagnostics/WLS_DIAGNOSTICS000000.DAT
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_OMS1/data/store/default/_WLS_EMGC_OMS1000000.DAT
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_ADMINSERVER/data/store/diagnostics/WLS_DIAGNOSTICS000000.DAT
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_ADMINSERVER/data/store/default/_WLS_EMGC_ADMINSERVER000000.DAT

and

[oracle@hostname gc_inst]$ find . -name "*.lok"
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/config/config.lok
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_OMS1/data/ldap/ldapfiles/EmbeddedLDAP.lok
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_OMS1/tmp/EMGC_OMS1.lok
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_ADMINSERVER/data/ldap/ldapfiles/EmbeddedLDAP.lok
$EM_INSTANCE_BASE/gc_inst/user_projects/domains/GCDomain/servers/EMGC_ADMINSERVER/tmp/EMGC_ADMINSERVER.lok

4) start the OMS

$/bin/emctl start OMS

 11g/12c OMS failed to start "Unable to obtain lock on EMGC_OMS1.lok" [ID 1302822.1]