Introduction

Upgrading your Oracle Cluster environment is a critical task that every DBA eventually faces. Whether it’s for security patches, new features, or performance improvements, staying updated is essential.

Oracle strongly recommends using the Out-of-Place Upgrade method when upgrading to Oracle Grid Infrastructure 19c because it offers minimal risk, faster rollback, and reduced downtime.

In this guide, we will walk through a step-by-step explanation of the Oracle Grid Infrastructure 19c Upgrade using the out-of-place approach, in a clear and practical way.

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What is Out-of-Place Upgrade?

An out-of-place upgrade means:

👉 Installing a new Grid Infrastructure home (GI_HOME)
👉 Upgrading the cluster to use the new home
👉 Keeping the old home untouched for rollback

In simple words:

You install a new version alongside the old one, then switch over.

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Out-of-Place vs In-Place Upgrade

Feature	Out-of-Place Upgrade	In-Place Upgrade
Risk	Low	Higher
Rollback	Easy	Difficult
Downtime	Minimal	Higher
Recommended	✔ Yes	❌ No

👉 Oracle recommends Out-of-Place Upgrade for production systems

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Architecture Diagram – Out-of-Place Upgrade Flow

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Prerequisites for Oracle Grid Infrastructure 19c Upgrade

Before starting the Oracle Grid Infrastructure 19c Upgrade, ensure:

✔ OS and Hardware Compatibility

• Verify using Oracle Certification Matrix

✔ Sufficient Disk Space

• New GI home requires separate location

✔ Backup Configuration

• OCR backup
• Voting disk backup
• Database backups

✔ Run Pre-Upgrade Check

$GRID_HOME/runcluvfy.sh stage -pre crsinst -upgrade

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Step-by-Step Out-of-Place Upgrade Process

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Step 1: Install New Grid Infrastructure Home

Install GI 19c in a new location:

/u01/app/19.0.0/grid

Run installer:

./gridSetup.sh

Select:

👉 Upgrade Oracle Grid Infrastructure

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Step 2: Run Prerequisite Checks

The installer automatically validates:

• Network
• Storage
• ASM
• Cluster configuration

Fix any errors before continuing.

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Step 3: Execute Root Upgrade Script

After installation:

Run on each node:

rootupgrade.sh

This performs:

✔ Clusterware upgrade
✔ ASM upgrade
✔ OCR update
✔ Voting disk update

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Step 4: Upgrade ASM and Disk Groups

Verify ASM compatibility:

SELECT name, compatibility FROM v$asm_diskgroup;

If needed:

ALTER DISKGROUP DATA SET ATTRIBUTE 'compatible.asm'='19.0';

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Step 5: Upgrade Clusterware Stack

Verify services:

crsctl check cluster -all

Check cluster resources:

crsctl stat res -t

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Step 6: Validate Upgrade

Use:

cluvfy comp cluster -post crsinst -upgrade

Ensure:

✔ All nodes active
✔ ASM running
✔ Voting disks healthy
✔ OCR healthy

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Rollback Strategy

One of the biggest advantages of out-of-place upgrade is easy rollback.

If something fails:

👉 You can switch back to old GI_HOME

Steps:

1. Stop new GI
2. Restart old GI home
3. Restore OCR backup

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Downtime Considerations

Out-of-place upgrade allows rolling upgrade in some scenarios.

But typically:

• CRS is stopped during final switch
• Downtime is minimal (few minutes)

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Security and Feature Improvements in 19c

Upgrading to Oracle Grid Infrastructure 19c gives:

✔ Improved ASM performance
✔ Better Cluster Health Monitoring
✔ Stronger security patches
✔ New AFD/ACFS enhancements
✔ Better memory management

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Real-World Upgrade Example

Production environment:

• 4-node RAC cluster
• 12.1.0.2 → 19c upgrade

Results after upgrade:

✔ 20% improvement in cluster stability
✔ Faster failover time
✔ Reduced CRS restart issues
✔ Better ASM rebalance performance

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Common Mistakes to Avoid

❌ Not taking OCR backup
❌ Not checking disk space
❌ Ignoring cluvfy errors
❌ Not validating network interfaces
❌ Mixing GI and DB home versions incorrectly

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Best Practices for Oracle Grid Infrastructure 19c Upgrade

✔ Always use out-of-place upgrade
✔ Test upgrade in staging environment
✔ Take full backups
✔ Use rolling upgrade when possible
✔ Validate after each step
✔ Monitor cluster logs

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Monitoring Logs During Upgrade

Important log files:

• $GRID_HOME/log/<node>/alert.log
• crsd.log
• ocssd.log
• asmcmd.log

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Easy Way to Remember

Out-of-Place Upgrade = Install New → Switch → Keep Old for Safety

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Conclusion

Upgrading your cluster to Oracle Grid Infrastructure 19c is a critical but manageable task when done correctly.

The Out-of-Place Upgrade method provides:

✔ Safer upgrade path
✔ Minimal downtime
✔ Easy rollback
✔ Better performance and stability

By following this Oracle Grid Infrastructure 19c Upgrade guide, DBAs can confidently upgrade their RAC environments with minimal risk and maximum efficiency.