A few days ago, we published a post talking about changes in Oracle 18c regarding versioning and patching.
As usual, each time a new release arrives, we take a look at the new features document to look for those things we were missing in Oracle and at least are available.
With 12c, we saw Flex ASM brought what its name seems to clearly indicate, flexibility for ASM access performed by database instances in a Real Application Cluster. From here, a database instance does not need, when using Flex ASM, a local ASM instance to be able to access storage. This way, 12c started giving a database instance the ability of surviving an local or remote ASM instance crash without disruption. We also could see that using ACFS for database storage, this protections can be extended to databases in 22.214.171.124, as we can read in this Sergio Menoyo’s post.
Oracle 18c announces improvements in high availability, introducing Zero Impact Patching. What does ZIP brings? The possibility for online patching when applying rolling upgrade Grid Infrastructure patches with maintaining the database instances running and with no user session disruption.
At the moment, there’s no much technical information regarding Zero Impact Patching, neither in install / upgrade guide for GI 18. We can find more information in Oracle’s official blog, in this 2017 Open World presentation, or in this Oracle 18 white paper. This documents tells us that these Grid Infrastructure updates will be out-of-place (with a new patched GI_HOME just like when applying Patch Sets starting with 11gR2). The change will be performed by means of stopping the old Clusterware and startup the new one, with no RDBMS instances being stopped in the process. Interesting, specially if this funcionality could finally be extended further, in example, giving the possibility of bouncing the Clusterware at any time with no disruption in database instances. We’ll see with the release of the 18c on-premise version (at the moment of writing, only Cloud and Engineered Systems versions are available) and with the future RURs the real possibilities of ZIP.