Applying Patches in Oracle Fusion Middleware ? Welcome to Zero DownTime (ZDT) Patch
In my Oracle Fusion Middleware Training for Apps DBAs, DBAs, and Middleware Admin, I was discussing about Patching as part of Module 10, where we cover various patching tools like opatch, bsu, psa for various products like SOA, WebLogic, OHS, WebCenter etc including Schema Patches.
One of the topic came was how to apply patches without impacting users so system remains available to business user. Well if this is what you are looking for then
A) First thing you must is highly available system (two or more node active-active cluster).
B) Secondly patch that you are applying must be Zero Downtime Patch (ZDT)
Well that then sparked few more obvious questions
Q: What is Zero DownTime Patches in Oracle Fusion Middleware ?
A: Zero Downtime Patch (ZDT) are patches in Oracle Fusion Middleware that can be applied without interrupting Fusion Middleware Service.
Q: How is Zero DownTime (ZDT) Patch help ?
A: This feature is useful for high availability environments where downtime is concern. You have two node cluster and would like to apply (ZDT) patch , and if patch is of type ZDT then you can run a system live with one site without patch and other with patch.
You do rolling patch, where services are down on 01 for patching while users are still accessing application via 02 side .
Once 01 side is fully patched and available back to users, you then bring down side 02 for applying same patch on 02 side. This way you apply patch without interrupting users accessing application .
This feature of patch help you applying patch with zero downtime to users accessible application .
Q: How do I know if patch is Zero Downtime Patch or not ?
A: Each Oracle Patch comes with Patch README containing steps to apply patch. Patch readme will say patch is FMW_ROLLING_HOME, FMW_ROLLING_ORACLE_HOME or FMW_ONLINE
You will see something on the lines of this for Zero Downtime Patch
This patch has been marked as eligible for Zero Downtime Patching. The type of Zero Downtime Patching supported by this patch is FMW_ROLLING_ORACLE_HOME.
References
- Zero Downtime Patching in Fusion Middleware (Doc ID 1942159.1)
- Information Center: Patching and Maintaining Oracle Fusion Middleware 11g (Doc ID 1341616.2)
- Preparing for Zero Downtime Patching in Oracle Fusion Middleware
