Zero Downtime Migration (ZDM):
Ashish Agnihotri
Data Analyst at Exaguru
Zero Downtime Migration (ZDM): The Future of Oracle Database Migrations
When it comes to modernizing Oracle Databases—whether moving from on-premises to Oracle Cloud Infrastructure (OCI), upgrading to the latest database version, or consolidating into Exadata Cloud—downtime is the biggest challenge.
This is where Zero Downtime Migration (ZDM) comes into play. ZDM is Oracle’s fully automated, out-of-the-box solution for seamless, secure, and minimal-risk database migrations with zero downtime for mission-critical workloads.
What is Zero Downtime Migration (ZDM)?
ZDM is an automated tool provided by Oracle that enables enterprises to migrate databases across platforms, data centers, or into the cloud—without impacting ongoing business operations.
It leverages Oracle’s proven high availability technologies, including Oracle Data Guard, GoldenGate, and RMAN, wrapping them into a single, automated framework for end-to-end migration.
Key Features of ZDM
- Zero Downtime – Users continue working while migration is in progress.
- Automation First – Orchestrates the entire process (configure → migrate → cutover).
- Multiple Migration Paths – Supports Data Guard, GoldenGate, and RMAN-based methods.
- Source/Destination Flexibility – On-Premises → OCI, Exadata Cloud@Customer, or Autonomous.
- Validation & Rollback – Pre-checks for readiness and rollback options for safety.
- Secure Transfers – Leverages encryption and Oracle best practices.
Benefits of Using ZDM
- Business Continuity: No disruption to end users.
- Lower Risk: Automated validation reduces human error.
- Faster Time-to-Cloud: Simplifies large-scale migrations.
- Cost-Efficient: Eliminates extended downtime costs.
- Future-Ready: Supports upgrades to Oracle 19c, 21c, and beyond.
ZDM Architecture
- Here’s how ZDM works at a high level:
- ZDM Service Host (installed on a separate VM/host) orchestrates the migration.
- Source Database (on-premises, Exadata, or VM) continues serving transactions.
- The target database (OCI, ExaCS, ExaCC, or Autonomous) is prepared.
- Data Guard/GoldenGate Sync ensures both databases remain in sync.
- Switchover happens at the final stage → business applications seamlessly switch to the new environment.
Popular Use Cases of ZDM
- On-Premises to OCI: Lift & shift with zero downtime.
- Exadata to Exadata Cloud@Customer (ExaCC): Seamless transition.
- Version Upgrades: Move from 11g/12c → 19c or 21c with continuous availability.
- Hybrid Cloud Migrations: Keep some workloads on-prem while moving critical databases to OCI.
- Mission-Critical Industries: Banking, Telecom, and E-commerce—where downtime = revenue loss.
Final Thoughts
Oracle’s Zero Downtime Migration (ZDM) is not just a tool—it’s a strategic enabler for organizations modernizing their database infrastructure. By automating the complexity and ensuring business continuity, ZDM makes it possible to embrace the cloud and new database versions without fear of disruption.
At ExaGuru, we help DBAs, architects, and IT leaders master ZDM migrations with step-by-step guides, hands-on labs, and real-world case studies.
Next Step: Lesson 1: ZDM Overview & Internals Explained
