WARNING: Limit of open file descriptors is found to be 1024

Problem: WARNING: Limit of open file descriptors is found to be 1024. The OMS has been started but it may run out of descriptors under heavy usage. For proper functioning of OMS, please set "ulimit -n" to be at least 4096. Example: $/u01/app/oracle/oem/Middleware/oms/bin/emctl start oms Oracle Enterprise Manager Cloud Control 12c Release 3 Copyright (c) 1996, 2013 Oracle Corporation.  All rights reserved. Starting Oracle Management Server... Starting WebTier... WebTier Successfully Started Oracle Management Server Successfully Started Oracle Management Server is Up WARNING: Limit of open file descriptors is found to be 1024. The OMS has been started but it may run out of descriptors under heavy usage. For proper functioning of OMS, please set "ulimit -n" to be at least 4096. Reason: Ulimit nofile parameter defines the maximum number of files that can be open by OS user.  According to Enterprise Manager Installation guide, “Ensure that you set the soft limit of file  descriptor to a minimum of 4096 and hard limit less then or equal to 16384.” which is  mention in installation guide: http://docs.oracle.com/cd/E24628_01/install.121/e22624/install_em_exist_db.htm#BGBHFCAB Steps to fix that: 1. Check ulimit for nofile soft $ ulimit -Sn    1024 2.  Stop the OMS $ <OMS_HOME>/bin/emctl stop oms -all 3.  Make sure there is no process running from the OMS ORACLE_HOME, kill if any: [oracle@xxxx-oem-01 ~]$ps -ef | grep EMGC_ADMINSERVER oracle     821 29991  0 08:14 pts/0    00:00:00 grep EMGC_ADMINSERVER [oracle@xxxx-oem-01 ~]$ps -ef | grep EMGC_OMS1 oracle     838 29991  0 08:15 pts/0    00:00:00 grep EMGC_OMS1 [oracle@xxxxx-oem-01 ~]$ps -ef | grep java oracle     840 29991  0 08:15 pts/0    00:00:00 grep java [oracle@fcias-oem-01 ~]$ $ kill -9 <PID> 4.  Increase the ulimit value to 4096. Update ulimit soft to 4096 in file /etc/security/limits.conf as root user $ vi /etc/security/limits.conf oracle soft nofile 4096 5.  Start the OMS $ <OMS_HOME>/bin/emctl start oms