Goldengate

This article picks up where the networking and storage setup left off. The Proxmox host (pve01.lab.example.com) is running with two VLAN-aware bridges, a ZFS mirror pool (vmpool), and shared ASM zvols already created. We now create all ten VMs using the qm CLI, configure shared storage for RAC, and verify each group before installing Oracle software. 1. VM Inventory and Resource Plan VM ID Hostname Role vCPU RAM OS Disk Notes 100 rac1-node1 RAC Cluster 1, Node 1 8 32 GB 80 GB Shared ASM 101 rac1-node2 RAC Cluster 1, Node 2 8 32 GB 80 GB Shared ASM 110 rac2-node1 RAC Cluster 2, Node 1 8 32 GB 80 GB Shared ASM 111 rac2-node2 RAC Cluster 2, Node 2 8 32 GB 80 GB Shared ASM 120 oms01 Enterprise Manager OMS 1 4 24 GB 80 GB + 200 GB data Primary OMS 121 oms02 Enterprise Manager OMS 2 4 24 GB 80 GB + 200 GB data Secondary OMS 130 okv01 Oracle Key Vault Primary 4 16 GB 80 GB TDE key store 131 okv02 Oracle Key Vault Secondary 4 16 GB 80 GB Paired node 140 ogg01 GoldenGate Microservices (Extract) 4 16 GB 80 GB + 200 GB trail OGG 23ai MA 141 ogg02 GoldenGate Microservices (Replicat) 4 16 GB 80 GB + 200 GB trail OGG 23ai MA Total: 56 vCPU / 240 GB RAM — host has 32 threads and 256 GB. vCPU is intentionally overcommitted (lab workloads are not all active simultaneously). RAM headroom: 16 GB for Proxmox host. ...

Active-active replication — where two or more databases accept writes simultaneously and replicate to each other — is one of the most powerful but also most operationally complex GoldenGate topologies. Without a robust conflict detection and resolution (CDR) strategy, you will silently corrupt data on one or both sides. This article covers CDR mechanics, built-in GoldenGate resolution handlers, and architectural patterns that minimise conflict occurrence in the first place. Why Conflicts Occur In a bidirectional topology, any row can be updated on either site concurrently. A conflict occurs when: ...

Oracle GoldenGate ships in two distinct deployment architectures: the Classic Architecture (the original GGSCI-based model) and the Microservices Architecture (introduced in 18c, fully mature from 21c). Both replicate data using the same trail-file and process model under the hood, but they differ substantially in how processes are deployed, managed, and monitored. Choosing the wrong one for your use case adds unnecessary operational complexity. The Fundamental Difference Dimension Classic Microservices Management interface GGSCI command-line REST API + Web UI Process model OS-level processes managed by Manager Microservices managed by Service Manager Configuration storage Flat parameter files (.prm) Internal repository (configurable) Deployment unit Single installation per host Service-based; multiple deployments per host OCI/Cloud-native fit Requires custom automation Native REST/API; integrates with OCI GoldenGate Security Parameter-file credentials Credential store + wallet Multi-tenancy (CDB) Limited Full PDB-level pipeline isolation Classic Architecture: Operational Model In Classic, the Manager process is the parent for all Extract, Pump, and Replicat processes. You interact with the system via GGSCI (GoldenGate Software Command Interface). ...

Migrating an Oracle database to OCI involves more than moving data — it requires selecting the correct migration toolchain, designing for cutover, and managing risk. Oracle provides multiple migration paths, and choosing incorrectly leads to extended downtime or data integrity issues. This article compares the major approaches and provides decision criteria. Migration Approach Decision Tree Is downtime during migration acceptable? ├── YES (hours or more acceptable) │ ├── Database size < 1 TB → Data Pump (expdp/impdp) over network or pre-stage to Object Storage │ └── Database size > 1 TB → RMAN duplicate or backup/restore to OCI Object Storage └── NO (near-zero or zero downtime required) ├── Source is Oracle → Zero Downtime Migration (ZDM) with GoldenGate └── Source is non-Oracle → OCI Database Migration Service (DMS) Zero Downtime Migration (ZDM) Oracle ZDM is the recommended tool for migrating Oracle databases to OCI with minimal or zero downtime. It orchestrates a combination of RMAN (initial bulk copy) + GoldenGate (ongoing replication during migration) in an automated workflow. ...

Oracle GoldenGate is the industry standard for heterogeneous, real-time data replication and change data capture (CDC). Despite being in use for decades, its internal mechanics are frequently misunderstood, leading to poorly tuned deployments that bottleneck at the wrong layer. This article dissects the architecture from the redo log all the way to the target apply. Architecture Overview A GoldenGate pipeline has three logical tiers: Capture — the Extract process mines redo/archive logs on the source database. Distribution — the Data Pump (a secondary Extract) reads local trail files and transmits them to a remote trail on the target host. Apply — the Replicat process reads the remote trail and applies changes to the target database. Each tier operates independently, connected only through trail files — sequential, compressed binary files that serve as a persistent, durable queue between processes. ...

This article presents a complete, real-world migration playbook for moving an Oracle Database from an on-premises Exadata X8 to Oracle Database@Azure Autonomous Database Serverless (ADB-S). The two data centres are 70 km apart, connected via a dedicated Azure ExpressRoute circuit. We use Oracle Zero Downtime Migration (ZDM) with GoldenGate replication to achieve a sub-minute application downtime. Environment Diagram ┌─────────────────────────────────────────────────────────────────┐ │ ON-PREMISES DATA CENTRE (Frankfurt) │ │ │ │ ┌──────────────────────────────────────────────────────────┐ │ │ │ EXADATA X8 FULL RACK │ │ │ │ │ │ │ │ ┌──────────────┐ ┌──────────────┐ │ │ │ │ │ x8db01 │ │ x8db02 │ Compute nodes │ │ │ │ │ (RAC inst1) │ │ (RAC inst2) │ │ │ │ │ └──────┬───────┘ └──────┬───────┘ │ │ │ │ └──────── IB ─────────┘ │ │ │ │ ┌──────────────────┐ │ │ │ │ │ Storage Cells │ (8 cells) │ │ │ │ │ x8cel01–x8cel08 │ │ │ │ │ └──────────────────┘ │ │ │ │ │ │ │ │ Database: ORCL (CDB), PDB: PDB_ERPSYS │ │ │ │ Size: 3.2 TB (data) + 400 GB indexes │ │ │ └──────────────────────────────────────────────────────────┘ │ │ │ │ ┌──────────────────────────────────────────────────────────┐ │ │ │ ZDM Service Host: zdmhost01.prod.example.com │ │ │ │ GoldenGate Extract: running on x8db01 (Integrated) │ │ │ └──────────────────────────────────────────────────────────┘ │ │ │ │ │ Azure ExpressRoute │ │ │ Dedicated, 10 Gbps, 70 km │ │ │ RTT: ~0.7 ms (measured) │ │ │ │ └─────────────────────┼──────────────────────────────────────────-─┘ │ ┌──────────────────────┼──────────────────────────────────────────┐ │ ORACLE DB@AZURE (West Europe — Amsterdam) │ │ │ │ │ ┌────────────────────▼──────────────────────────────────────┐ │ │ │ Oracle Database@Azure — ADB-S │ │ │ │ Display Name: adb-erpsys-prod │ │ │ │ DB Name: ADBERPSY │ │ │ │ Shape: 16 OCPUs, auto-scale │ │ │ │ Storage: 10 TB (elastic) │ │ │ │ TLS: mTLS (wallet-based) │ │ │ │ │ │ │ │ OCI GoldenGate (Managed Microservices deployment) │ │ │ │ GG Service: gg-erpsys-deployment │ │ │ │ Replicat: REP_ERPSYS (Integrated) │ │ │ └────────────────────────────────────────────────────────────┘ │ └──────────────────────────────────────────────────────────────────┘ Network Architecture On-Premises Exadata Azure ExpressRoute Oracle DB@Azure (Frankfurt DC) (Dedicated, 10 Gbps) (Amsterdam) 10.10.0.0/16 ───────────────────────────────────────► 172.16.0.0/16 Key Network Points: x8db01 public IP: 10.10.1.101 x8db01 SCAN IP: 10.10.1.200 (for GoldenGate source connection) zdmhost01: 10.10.5.50 OCI GoldenGate GW: 172.16.10.10 (private endpoint) ADB-S private EP: 172.16.20.5 (private endpoint in Oracle DB@Azure VNet) ExpressRoute Circuit: Provider: equinix-frankfurt Bandwidth: 10 Gbps dedicated Measured RTT (Frankfurt → Amsterdam): 0.7 ms Throughput achieved (iperf3): 9.2 Gbps (92% of capacity) Reference Environment SOURCE (On-Premises Exadata X8): RAC node 1: x8db01.prod.example.com (oracle user) RAC node 2: x8db02.prod.example.com Storage cells: x8cel01–x8cel08.prod.example.com ZDM host: zdmhost01.prod.example.com (oracle user, ZDM installed here) DB unique name: ORCL PDB: PDB_ERPSYS Data size: 3.2 TB DB version: 19.18.0.0 TARGET (Oracle DB@Azure): Region: Azure West Europe (Amsterdam) Resource Group: rg-oracle-prod ADB name: adb-erpsys-prod ADB DB Name: ADBERPSY Service name: adberpsy_high (high priority service) mTLS wallet dir: /etc/oracle/adb_wallet/ (on zdmhost01) OCI GG deploy: gg-erpsys-deployment (Microservices, managed by Oracle) OCI GG version: 21c ADMIN JUMP HOST: admin01.prod.example.com (used for OCI CLI, ZDM monitoring) Phase 1: Pre-Migration Assessment 1.1 Network Latency and Throughput Validation Before any migration work, validate the ExpressRoute circuit performance from the ZDM host: ...