Downtime Reduction during Patching in R12.0/R12.1

1) Oracle now supports the Shared Application-Tier System. If you have multiple Application Servers using Load Balancing, then all the servers can share one single shared Application-Tier. Use Metalink Note: 233428.1 for 11i, and 384248.1 for Release 12. Patches  applied to shared application tiers are instantly
available to all application tiers

2) Shared application tier systems, distributed AD (Note:236469.1) can be used to run adpatch and adctrl on multiple nodes, that share the application tier file system

3)Staged Application Systems  Metalink Note: 242480.1, where patches are applied to a stage area, before the production upgrade, and then only the database portion is applied on the Production Instance thus reducing downtime

4) Merge multiple patches into smaller number of patches using AD Merge

5) AD Patch can be run in non-interactive mode, by creation of defaultsfile, and then creating batch programs which will runs series of patches one after the other without asking any questions.

6) Use options like “nocompiledb”, which will not compile all objects every time it applies a patch. Only the last patch can have the “compiledb” option.