ZDM (Zero Downtime Migration)

 

Oracle ZDM (Zero Downtime Migration) is a tool provided by Oracle to migrate Oracle databases with minimal or zero downtime. 

It is especially useful for migrating production databases to Oracle Cloud or newer versions of Oracle Database.

Key Use Cases of Oracle ZDM:

1. On-Premises to Oracle Cloud

Migrate databases from on-premises to:

○ Oracle Cloud Infrastructure (OCI)

○ Oracle Autonomous Database

○ Oracle Exadata Cloud@Customer

2. Version Upgrade with Migration

Upgrade from older versions (e.g., 11g, 12c, 18c) to 19c or 21c during migration.

3. Platform or Storage Change

Migrate databases across different platforms (e.g., Linux to Exadata) or storage types (e.g., File System to ASM).

NOTES:

• Oracle ZDM will run on a separate node and connect to both source and target to perform the migration. 

• Oracle ZDM supports both Physical and Logical Migration workflows.

• Oracle ZDM supports the following Oracle Database versions: 11.2.0.4, 12.1.0.2, 12.2.0.1, 18c, 19c, 21c.

• The source and target databases should be in the same database version.

• Oracle ZDM supports Oracle Databases hosted on Linux operating systems.

• The source database can be a single instance database migrating to a single instance or a RAC database, or it can also be a RAC One Node / RAC database, migrating to a RAC database. 

• ZDM supports Oracle Database 11g release 2 (11.2.0.4) or later versions, it is important that both the source and target are at the same release version.

• The target database version should be the same as the source database version. 

• The target database patch level should also be the same as (or higher than) the source database, if the target database is at a higher patch level than the source database, the customer must run datapatch after the database migration has taken place. 

How it Achieves Zero Downtime:

ZDM uses technologies like:

• Oracle Data Guard

• RMAN Incremental Backups

• Oracle GoldenGate (for near-zero downtime, especially when active replication is needed)

Advantages:

• Minimal or zero production downtime

• Automated orchestration

• Reduces human error

• Supports large mission-critical databases