This is the start of a blog post series on patching Oracle Grid Infrastructure 19c (GI). It is supposed to be easy to follow, so that I may have skipped a detail here and there.
I know my way around database patching. I have done it countless times. When it comes to GI, it’s the other way around. I have never really done it in the real world (i.e., before joining Oracle) and my knowledge was limited. I told my boss, Mike, and he gave me a challenge: Learn about it by writing a blog post series.
Why Do I Need to Patch Oracle Grid Infrastructure
Like any other piece of software, you need to patch GI to get rid of security issues and fix issues.
You should keep the GI and Oracle Database patch level in sync. This means that you need to patch GI and your Oracle Database at the same cadence. Ideally, that cadence is quarterly.
It is supported to run GI and Oracle Database at different patch levels as long as they are on the same release. GI is also certified to run some of the older Oracle Database releases. This is useful in upgrade projects. Check Oracle Clusterware (CRS/GI) – ASM – Database Version Compatibility (Doc ID 337737.1) for details.
A few examples:
|19.18.0||19.18.0||Yes – recommended|
|19.18.0||188.8.131.52||Yes – used during upgrade, for instance|
If possible and not too cumbersome, I recommend that you first patch GI and then Oracle Database. Some prefer to patch the two components in two separate operations, while others do it in one operation.
Which Patches Should You Apply to Oracle Grid Infrastructure
You should apply:
- Latest Release Update
- Monthly Recommend Patches (MRP), if such is already available
- Important fixes from 555.1, if any
Whether you download the bundle patches individually or go with the combo patch is a matter of personal preference. Ultimately, they contain the same.
Some prefer an N-1 approach: When the April Release Update comes, they patch with the previous one from January; Always one quarter behind. For stability reasons, I assume.
What about OJVM patches for GI? The short answer is no.
Which Method Do I Use For Patching
You can patch in two ways:
- In-place patching
- Out-of-place patching
|You apply patches to an existing Grid Home.||You apply patches to a new Grid Home.|
|You need disk space for the patches.||You need disk space for a brand new Grid Home and the patches.|
|You patch the existing Grid Home. When you start patching a node, GI drains all connections and moves services to other nodes. The node is down during patching.||You create and patch a new Grid Home without downtime. You complete patching by switching to the new Grid Home. The node is down only during switching.|
|Longer node downtime.||Shorter node downtime.|
|No changes to profile and scripts.||Profile, scripts and the like must be updated to reflect the new Grid Home.|
|My recommended method.|
Note: When I write node downtime, it does not mean database downtime. I discuss it shortly.
In other words:
In-place patching replaces the Oracle Clusterware software with the newer version in the same Grid home. Out-of-place upgrade has both versions of the same software present on the nodes at the same time, in different Grid homes, but only one version is active.
Oracle Fleet Patching and Provisioning
When you have more systems to manage, it is time to consider Fleet Patching and Provisioning (FPP).
Oracle Fleet Patching & Provisioning is the recommended solution for performing lifecycle operations (provisioning, patching & upgrades) across entire Oracle Grid Infrastructure and Oracle RAC Database fleets and the default solution used for Oracle Database Cloud services
It will make your life so much easier; more about that in a later blog post.
Zero Downtime Oracle Grid Infrastructure Patching
As of 19.16.0 you can also do Zero Downtime Oracle Grid Infrastructure Patching (ZDOGIP).
Use the zero-downtime Oracle Grid Infrastructure patching method to keep your Oracle RAC database instances running and client connections active during patching.
ZDOGIP is an extension to out-of-place patching. But ZDGIOP will not update the operating system drivers and will not bring down the Oracle stack (database instance, listener etc.). The new GI takes over control of the Oracle stack without users noticing. However, you must update the operating system drivers by taking down the node. But you can postpone it to a later point in time.
More details about ZDGIOP in a later blog post.
What about Oracle Database Downtime
When you patch GI on a node, the node is down. You don’t need to restart the operating system itself, but you do shut down the entire GI stack, including everything GI manages (database, listeners etc.).
What does that mean for Oracle Database?
If you have a single instance database managed by GI, your database is down during patching. Your users will experience downtime. By using out-of-place patching, you can reduce downtime.
If you have a Data Guard configuration, you can hide the outage from the end users.
First, you patch GI on your standby databases, then perform a switchover, and finally patch GI on the former primary database.
The only interruption is the switchover; a brownout period while the database switches roles. In the brownout period, the database appears to hang, but underneath the hood, you wait for the role switch to complete and connect to the new primary database.
If you have configured your application properly, it will not encounter any ORA-errors. Your users experience a short hang and continue as if nothing had happened.
If you have a RAC database, you can perform the patching in a rolling manner – node by node.
When you take down a node for patching, GI tells connections to drain from the affected instances and connect to other nodes.
If your application is properly configured, it will react to the drain events and connect seamlessly to another instance. The end users will not experience any interruption nor receive any errors.
If you haven’t configured your application properly or your application doesn’t react in due time, the connections will be forcefully terminated. How that will affect your users depend on the application. But it won’t look pretty.
Unless you configure Application Continuity. If so, the database can replay any in-flight transaction. From a user perspective, all looks fine. They won’t even notice that they have connected to a new instance and that the database replayed their transaction.
Other Blog Posts in This Series
- How to Patch Oracle Grid Infrastructure 19c Using In-Place OPatchAuto
- How to Patch Oracle Grid Infrastructure 19c Using Out-Of-Place OPatchAuto
- How to Patch Oracle Grid Infrastructure 19c Using Out-Of-Place SwitchGridHome
- How to Patch Oracle Grid Infrastructure 19c Using Zero Downtime Oracle Grid Infrastructure Patching
- Which Method Should I Choose When Patching Oracle Grid Infrastructure 19c
- How to Avoid Interruptions When You Patch Oracle Grid Infrastructure 19c
- Patching Oracle Grid Infrastructure And Oracle Data Guard
- Use Cluster Verification Utility (cluvfy) and Avoid Surprises
- A Word about Zero Downtime Oracle Grid Infrastructure Patching
- Why You Need to Use Oracle Fleet Patching and Provisioning
- My Best Advice on Patching Oracle Grid Infrastructure
- Pro Tips
- Blog post: Application Continuity – A Database Feature for Developers
- Technical Brief: Continuous Availability – MAA Checklist for Applications for the Oracle Database
- Technical Brief: Oracle Clusterware – What’s New with Oracle Clusterware
- MOS note: Zero-Downtime Oracle Grid Infrastructure Patching (ZDOGIP). (Doc ID 2635015.1)