By Akanksha Sheoran Kaler on Aug 22, 2013
As Product Manager for Oracle Enterprise Manager, one question that is often being asked to me is how much is the upgrade downtime and how it can be reduced?
One easy way to reduce the downtime while doing patch set upgrades is to perform Software only upgrade and then shutdown the existing OMS for the upgrade. This approach will not completely eliminate the downtime but reduce it to a great extent.
When I mention patch set upgrade, we cover following upgrade paths:
a) 18.104.22.168 (with Bundle Patches 1) to 22.214.171.124/ 126.96.36.199
b) 188.8.131.52 to 184.108.40.206
Following table compares the steps required for regular installation (OUI) and software only installation.
As you may notices from the steps listed above, regular OUI upgrade requires stopping OMS before invoking runInstaller and keeping it down until the upgrade is complete. On the other hand Software only upgrade first copies the bits and sets up the environment before stopping OMS, thus reducing the upgrade downtime.
Next comes Agent upgrade. While we recommend Agent Upgrade Console (AUC) to upgrade agents from 220.127.116.11 (with bundle patch1) /12.0.1.02 to 18.104.22.168, sometimes it’s not clear what happens during the Agent upgrade and when is the actual downtime . So here are high level steps describing the complete process:
The actual downtime while doing the agent upgrade is on step9 where we shut down your old agent. When the agent is in blackout from step 1 to 8 it still collect’s all the monitoring data so there is no loss.
More Information: It is recommended to go through the below checklist notes before starting your upgrade
MOS note 1568143.1 - EM 12c R3: Checklist for Upgrading Enterprise Manager Cloud Control from Version 12.1.0.x to 22.214.171.124
MOS Note 1569883.1 EM 12c R3: Checklist for Upgrading Management Agents Version 12.1.0.x to 126.96.36.199
EM 188.8.131.52 Install and Upgrade collateral page(PPT,Recorded demo,Whitepapers) on OTN:http://www.oracle.com/technetwork/oem/install-upgrade/index.html