Oracle Zero DownTime Migration Tool


Millennium IT ESP once again concluded a successful “First in Sri Lanka” Database Migration using the Zero Downtime Migration Tool (ZDM), to port an On-premises Oracle Exadata Database to Oracle Exadata Cloud Services. This mission-critical and only zero downtime-tolerable database was part of one of the largest telecommunication providers in the country, who are on the verge of moving their databases to Oracle Cloud infrastructure (OCI), with an expectation of deriving the best out of the public cloud offering including scalability, availability, and manageability.

As the name suggests, ZDM was explicitly chosen to meet zero disruption application availability, and we at MIT ESP, as a trusted partner for cutting-edge technology deployments, managed to fulfill the customers’ expectations by seamlessly migrating the database to the cloud. While this wasn’t the only database the customer had migrated to the cloud, more such databases are in line to be migrated to OCI.

Efforts of MIT ESP resources had to validate the complexity of the migration process as well as the right variation of the ZDM tool. With version and architecture changes in place, we opted to proceed with Logical Online Migration that included supplementary technologies such as Oracle GoldenGate (OGG HUB) and the ZDM Software itself.

Why ZDM?

Oracle ZDM is a simple, automated solution for moving Oracle Databases into the Oracle Cloud. Oracle ZDM performs zero-downtime migrations in smart steps, which can be scheduled and monitored. Oracle ZDM offers fully automated database migration by leveraging Oracle Maximum Availability Architecture best practices and orchestrating Oracle’s best products and tools like Data Pump, Recovery Manager (RMAN), Data Guard, GoldenGate, and others.

ZDM offers four different migration methods / Variations:

  • Logical Online Migration using GoldenGate
  • Logical Offline Migration using Data Pump
  • Physical Online Migration using Data Guard
  • Physical Offline Migration using RMAN

What are the supported versions?

ZDM supports Oracle database release and later. It supports single instances, Oracle Restart, and Oracle RAC configurations.

How ZDM Tool helped us?

As mentioned earlier, to meet customers’ availability requirements, the MIT ESP team proceeded with the ZDM Online Logical Migration approach. The Oracle GoldenGate (OGG) service and resources were obtained from the OCI marketplace at no cost, and Datapump was chosen to capture the initial load. OGG continued to replicate changes since the initial load from the source (on-premises) to the destination (Cloud). ZDM had the capabilities of automatic housekeeping, making the administrative work minimal.

What are the key features of ZDM tool?

  • Audit Trail: Monitor every action during migration, ensuring transparency and accountability.
  • Customizable Workflow: Tailor migration steps to your specific needs with flexible phases and plugins.
  • Fleet-Scale Management: Effortlessly manage migrations across your entire database fleet for enhanced efficiency.
  • Flexible Scheduling: Plan migrations to minimize disruptions, scheduling them at convenient times.
  • Pause and Resume: Exercise control over migrations with pause and resume options, accommodating interruptions or maintenance.
  • Rerun Capability: Easily restart migrations from the point of failure for seamless progress.
  • Pre-Check Validation: Prevent errors with comprehensive pre-migration checks, ensuring a smooth transition.
  • Compliance Assurance: Rest assured, knowing the service complies with industry standards and fully supports Oracle databases.

Business Benefits

As the world sees the benefits of various cloud offerings, the tendency to migrate workloads to multicloud and hybrid cloud combinations has become very aggressive. While applications can be pre-provisioned on destination clouds, migrating ever-changing data within databases raises challenges, especially due to their high availability requirements. Additionally, the cost of migration becomes significant for such critical databases.

ZDM addresses both of the above challenges by way of a methodical use case-based approach at no additional cloud cost, to support zero downtime migrations and meet end-user SLAs. ZDM proves to be a reliable approach to database migration as it leverages Oracle’s own proven technology stack.


With its user-friendly features and assurance of compliance, the Zero Downtime Migration service elevates and simplifies the Oracle Cloud migration experience at no additional cost, setting a new standard for database management technology. As a trusted partner, MIT ESP is always ready to fulfill customers’ expectations efficiently and impeccably.


Kavindu Edirisinghe

Associate Engineer – Database and Middleware