sqlplus / as sysdba
show parameter db_recovery;

sys@EM13REP> show parameter db_recovery;

NAME                                 TYPE        VALUE
==================================== =========== ==============================
db_recovery_file_dest                string      /u07/flashback
db_recovery_file_dest_size           big integer 17G

to change to different directory
sys@EM13REP> alter system set db_recovery_file_dest='/u07/flashback';

to change recovery file size
sys@EM13REP> alter system set db_recovery_file_dest_size='17g';

database is open
sys@EM13REP> alter database flashback on;

ls /u07/flashback

list restore points
SQL> SELECT NAME, SCN, TIME, DATABASE_INCARNATION#, GUARANTEE_FLASHBACK_DATABASE,STORAGE_SIZE FROM V$RESTORE_POINT;

SQL> CREATE RESTORE POINT before_upgrade;

​sys@EM13REP> select flashback_on from v$database;

​
Reference: 
​http://docs.oracle.com/database/122/BRADV/using-flasback-database-restore-points.htm#BRADV71000

You have found that the time zone is wrong on a particular agent. This agent is already communicating with the OMS. Additionally, you determine that the host is of the wrong timezone. This blog documents the steps required to correct this situation.

It appears that host "mengland-lnx" is on the wrong timezone

The host should be set to the Pacific Timezone.

Check the Repository Database:
sql> select target_name, timezone_region
from sysman.mgmt_targets
where target_name='mengland-lnx'
order by 1,2;

TARGET_NAME
====================================================================================================
TIMEZONE_REGION
================================================================
mengland-lnx
US/Mountain
____________________________________________________________________________________________________

Yes wrong timezone

Connect to the host "mengland-lnx"

# date
Sat Nov 19 16:28:05 MST 2016

# cd /etc

# ls -al localtime
lrwxrwxrwx 1 root root 31 Nov 18 20:05 localtime -> /usr/share/zoneinfo/US/Mountain

# rm localtime

All US timezones are located under the /usr/share/zoneinfo/US directory.
# ls /usr/share/zoneinfo/US

# cd /etc
# ln -s /usr/share/zoneinfo/US/Pacific localtime

# date
Sat Nov 19 15:31:37 PST 2016

Host is fixed now let's fix the EM Agent
.[oracle]$ ./emctl stop agent
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
Stopping agent ... stopped.

[oracle]$ ./emctl resetTZ agent
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
Updating /oem/app/oracle/product/agent13c/agent_inst/sysman/config/emd.properties...
Successfully updated /oem/app/oracle/product/agent13c/agent_inst/sysman/config/emd.properties.
Login as the em repository user and run the  script:
exec mgmt_target.set_agent_tzrgn('mengland-lnx:3872','US/Pacific')
and commit the changes
This can be done for example by logging into sqlplus and doing
SQL> exec mgmt_target.set_agent_tzrgn('mengland-lnx:3872','US/Pacific')
SQL> commit

sysman@EM13REP> exec mgmt_target.set_agent_tzrgn('mengland-lnx:3872','US/Pacific')

PL/SQL procedure successfully completed.

sysman@EM13REP> commit;

Commit complete.

Check the EM Repository again

sysman@EM13REP> select target_name, timezone_region
from sysman.mgmt_targets
  2    3  where target_name='mengland-lnx'
  4  order by 1,2;

TARGET_NAME
====================================================================================================
TIMEZONE_REGION
================================================================
mengland-lnx
US/Pacific
____________________________________________________________________________________________________

Start the agent now
[oracle]$ ./emctl start agent
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
Starting agent ................ started.

[oracle]$ ./emctl config agent getTZ
Oracle Enterprise Manager Cloud Control 13c Release 2
Copyright (c) 1996, 2016 Oracle Corporation.  All rights reserved.
US/Pacific

PREPARE THE HOST

/u01 50GB
/u10 50GB
/ 400GB

as root
yum repolist
yum update
yum search preinstall
yum install oracle-database-server-12cR2-preinstall

visudo
## Allow root to run any commands anywhere
oracle  ALL=(ALL)       ALL
## Same thing without password
%dba    ALL=(ALL)       NOPASSWD: ALL

vi /etc/hosts
## make sure your fqhn is in here for MT and DB
192.168.1.113 aemidbs04.localdomain aemidbs04
192.168.1.114 aemimts01.localdomain aemimts01

vi /etc/sysconfig/network
## make sure your HOSTNAME= value is populated

Hey Add more RPM's
# OL6 and OL7
yum install make -y
yum install binutils -y
yum install gcc -y
yum install libaio -y
yum install glibc-common -y
yum install libstdc++ -y
yum install libXtst -y
yum install sysstat -y
yum install glibc -y
yum install glibc-devel -y
yum install glibc-devel.i686 -y

as root
mkdir -p /u01/app/oracle/product/emgc13c
mkdir -p /u01/app/oracle/product/agent13c
mkdir -p /u10/shiphome/em13
mkdir -p /u10/scratch

chown -R oracle:dba /u01
chown -R oracle:dba /u10

as
vi /etc/oraInst.loc
inventory_loc=/u01/app/oracle/product/oraInventory
inst_group=oinstall
chmod 755 /etc/oraInst.loc

INSTALL THE SOFTWARE

as oracle
cd /u10/shiphome/em13
download the software
http://www.oracle.com/technetwork/oem/grid-control/downloads/oem-linux64-2823270.html

as root
vi /etc/oracle-release
change 6.8 
to 6.5
remember to change back after installation

as root
sysctl -w net.ipv4.ip_local_port_range="11000 65000"
check
​sysctl net.ipv4.ip_local_port_range

use vncviewer to connect and run the installer
/u10/shiphome/em13/em13100_linux64.bin -J-Djava.io.tmpdir=/u10/scratch/ -invPtrLoc /etc/oraInst.loc

​Install Software Only
​
​/u01/app/oracle/product/emgc13c/sysman/install/ConfigureGC.sh

as root
yum repolist
yum update
yum search preinstall
yum install oracle-database-server-12cR2-preinstall

visudo
## Allow root to run any commands anywhere
oracle  ALL=(ALL)       ALL
## Same thing without a password
%dba    ALL=(ALL)       NOPASSWD: ALL

vi /etc/hosts
## Make sure FQHN and Alias are in here, for both MT and DB
192.168.1.113 aemidbs04.localdomain aemidbs04
192.168.1.114 aemimts01.localdomain aemimts01

# OL6 and OL7, most packages will already be there
yum install binutils -y
yum install compat-libcap1 -y
yum install compat-libstdc++-33 -y
yum install compat-libstdc++-33.i686 -y
yum install gcc -y yum install gcc-c++ -y
yum install glibc -y yum install glibc.i686 -y
yum install glibc-devel -y
yum install glibc-devel.i686 -y
yum install ksh -y yum install libgcc -y
yum install libgcc.i686 -y
yum install libstdc++ -y
yum install libstdc++.i686 -y
yum install libstdc++-devel -y
yum install libstdc++-devel.i686 -y
yum install libaio -y
yum install libaio.i686 -y
yum install libaio-devel -y
yum install libaio-devel.i686 -y
yum install libXext -y
yum install libXext.i686 -y
yum install libXtst -y
yum install libXtst.i686 -y
yum install libX11 -y
yum install libX11.i686 -y
yum install libXau -y
yum install libXau.i686 -y
yum install libxcb -y
yum install libxcb.i686 -y
yum install libXi -y
yum install libXi.i686 -y
yum install make -y
yum install sysstat -y
yum install unixODBC -y
yum install unixODBC-devel -y

mkdir -p /u01/app/oracle/product/12cDB
mkdir -p /u05/oradata
mkdir -p /u07/archive
mkdir -p /u10/shiphome

chown -R oracle:dba /u01
chown -R oracle:dba /u05
chown -R oracle:dba /u07
chown -R oracle:dba /u10

# Set Password for Oracle
passwd oracle

# Update 90-nproc.conf ... ref. MOS Note
vi /etc/security/limits.d/90-nproc.conf
# Change this * soft nproc 1024
# To this * - nproc 16384

# Change selinux
vi /etc/selinux/config
SELINUX=permissive

# Run Setenforce
setenforce Permissive

# Turn off Firewall
service iptables stop
chkconfig iptables off

as root
xhost + <hostname.localdomain>

vi /etc/oraInst.loc
inventory_loc=/u01/app/oracle/product/oraInventory
inst_group=oinstall

as oracle
download the oracle database software
http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html
to this location /u10/shiphome

as oracle
download the oracle database template for 13c
http://www.oracle.com/technetwork/oem/enterprise-manager/downloads/db-templates-2767916.html
to this location /u10/shiphome

as oracle
cd /u10/shiphome
cksum *  
unzip linuxamd64_12102_database_1of2.zip
unzip linuxamd64_12102_database_2of2.zip

as oracle
DISPLAY=<hostname.localdomain>:0.0; export DISPLAY

./runInstaller