In this blog post, We will discuss Oracle Active Data Guard and Oracle GoldenGate. While Oracle Active Data Guard and Oracle GoldenGate are each capable of maintaining a synchronized copy of an Oracle database, each has unique characteristics that result in high availability architectures that can use one technology or the other, or both at the same time, depending upon requirements.
When to Use Oracle Active Data Guard?
You can use Oracle Active Data Guard when the emphasis is on simplicity, data protection, and availability.
1- Simplest, fastest, one-way replication of a complete Oracle database.
2- No restrictions: Data Guard Redo Apply supports all data and storage types and Oracle features; transparent replication of DDL
3- Features optimized for data protection: Detects silent corruptions that can occur on source or target; automatically repairs corrupt blocks
4- Synchronized standby open read-only provides simple read-only offloading for maximum ROI
5- Transparency of backups: A Data Guard primary and standby are physically exact copies of each other; RMAN backups are completely interchangeable
6- Zero data loss protection at any distance, without impacting database performance
7- Minimizing planned downtime and risk using standby first patching, database rolling upgrades, and select platform migrations
8- Reduce risk of introducing change by dual purposing a DR system for testing using Data Guard Snapshot Standby
9- Integrated automatic database and client failover
10 –Integrated management of a complete configuration: Data Guard Broker command line interface or Oracle Enterprise Manager Cloud Control.
When to Use Oracle GoldenGate?
You can use Oracle GoldenGate when the emphasis is on advanced replication requirements not addressed by Oracle Active Data Guard.
1- Any requirement where the replica database must be open read/write while synchronizing with the primary database
2- Any data replication requirements such as multimaster and bidirectional replication, subset replication, many-to-one replication, and data transformations.
3- When data replication is required between endian format platforms or across-database major versions.
4- Maintenance and migrations where zero downtime or near zero downtime is required. Oracle GoldenGate can be used to migrate between application versions without downtime.
5- Database rolling upgrades where it is desired to replicate from new version down to the old version for the purpose of fast fall-back if something is wrong with the upgrade.
6- Zero downtime planned maintenance where bidirectional replication is used to gradually migrate users to the new version, creating the perception of zero downtime. Note that bidirectional replication requires avoiding or resolving update conflicts that can occur on disparate databases.
When to Use Oracle Active Data Guard and Oracle GoldenGate Together?
Oracle Active Data Guard and Oracle GoldenGate are not mutually exclusive. The following are use cases of high availability architectures that include the simultaneous use of Oracle Active Data Guard and Oracle GoldenGate.
1- An Oracle Active Data Guard standby is utilized for disaster protection and database rolling upgrades for a mission critical OLTP database. At the same time, Oracle GoldenGate is used to replicate data from the Data Guard primary database (or from the standby database using Oracle GoldenGate ALO mode) for ETL update of an enterprise data warehouse.
2- Oracle GoldenGate subset replication is used to create an operational data store (ODS) that extracts, transforms, and aggregates data from numerous data sources. The ODS supports mission critical application systems that generate significant revenue for the company. An Oracle Active Data Guard standby database is used to protect the ODS, providing optimal data protection and availability.
3- Oracle GoldenGate bidirectional replication is utilized to synchronize two databases separated by thousands of miles. User workload is distributed across each database based upon geography, workload, and service level using Oracle 12c Global Data Services (GDS). Each Oracle GoldenGate copy has its own local synchronous Data Guard standby database that enables zero data loss failover if an outage occurs. Oracle GoldenGate capture and apply processes are easily restarted on the new primary database following a failover because the primary and standby are an exact, up-to-date replica of each other.
4- An Oracle Active Data Guard standby database used for disaster protection is temporarily converted into an Oracle GoldenGate target for the purpose of performing planned maintenance not supported by Data Guard. For example, a Siebel application upgrade requiring modification of back-end database objects which require comprehensive testing before switching users over to the new system.
5- Oracle Active Data Guard is used to protect a production environment when a major database version upgrade is required offering zero or near-zero downtime (for example, Oracle 188.8.131.52 to 12c.) A second primary/standby environment is created using the new database version, and Oracle GoldenGate is used to replicate data from the production environment to the copy with one-way or bidirectional replication. When Oracle GoldenGate has completed synchronizing the old and new environments, production is switched to the new environment and the old environment is decommissioned. This provides zero or minimal downtime depending upon configuration, eliminates risk by providing complete isolation between the old and new environment, and avoids any impact to data protection and availability SLAs if problems are encountered during the upgrade process.