Current Situation and Disaster Recovery Requirements Investigation

  • Existing High Availability Solution
    • Currently implemented dual-active between two computer rooms using VPLEX-based Extended RAC
  • Source Database Information
    • Operating System: 64-bit AIX 7100
    • Database: Oracle 12.1.0.2 Extended RAC
  • Disaster Recovery Site Requirements
    • Achieve data disaster recovery for data protection
    • Used for data extraction by other services
  • Disaster Recovery Environment Hardware and OS
    • Based on existing resources, there is one one-eighth rack Exadata in both the production and standby computer rooms. Current database version is 11.2.0.3.
  • Disaster Recovery Synchronization Options Considered
    • ADG
    • OGG

Comparison of Logical Replication (OGG) and Physical Replication (ADG)

  • Scenarios Where OGG Excels
    • Supports read-write on both sides
    • Supports cross-platform (AIX and Linux)
    • Supports cross-version (requires validation of supported versions)
  • Scenarios Where ADG Excels
    • OGG only supports asynchronous mode, cannot achieve zero data loss; ADG supports zero data loss.
    • ADG has block auto-repair functionality, OGG does not.
    • OGG data validation is less strict than ADG.
    • OGG has some data type limitations, e.g., the same ROWID may represent different records or even different objects on source and target.
    • Large DML operations cause more significant delays in OGG.
    • ADG configuration and maintenance are simpler.
    • OGG source and target backups cannot be used interchangeably.

Summary of OGG and ADG

  • ADG is the preferred choice for data disaster recovery protection.
  • Can also be used for backups on the standby side, offloading read-only operations from the source to the standby.
  • Oracle strongly recommends deploying an ADG environment, which can be used both for data distribution to data warehouses and as a supplement to disaster recovery providing additional protection.
  • OGG is more suitable for cross-version, cross-platform scenarios requiring write operations on the disaster recovery end.
  • Architecturally, with the source environment being 64-bit AIX, direct replication via ADG to a target environment of 64-bit X86 Linux is not supported.
  • Additionally, the current Oracle database version on Exadata is 11.2.0.3, which is unsupported. It is recommended to upgrade to 12.1.0.2.