Oracle Data Guard is a feature of Oracle Database that helps manage standby databases to ensure high availability, data protection, and disaster recovery for enterprise data.
🛡️ What is Data Guard?
Oracle Data Guard creates and maintains one or more standby copies (or replicas) of your primary (production) database. These standby databases are synchronized with the primary, either in real-time or near real-time, so they can take over immediately if the primary fails.
⚙️ Components of Data Guard
- Primary Database
The active, production database used by applications.
- Standby Database
A copy of the primary database. Types include:
Physical Standby: Exact block-for-block copy using redo logs.
Logical Standby: Uses SQL apply; can be open read-write (for reporting).
Snapshot Standby: Can be used temporarily for testing.
- Redo Transport Services
Transfers redo data from primary to standby.
- Apply Services
Applies redo on standby to keep it updated.
- Data Guard Broker (Optional)
A management and automation tool for Data Guard.
🌟 Importance of Data Guard
Benefit Description
- Disaster Recovery If the primary database fails (due to hardware failure, natural disaster, etc.), a standby can quickly take over.
- High Availability Ensures business continuity with minimal downtime.
- Data Protection Prevents data loss with synchronous or asynchronous data transfer.
- Load Balancing Logical or snapshot standbys can handle reporting or queries to reduce load on the primary.
- Automated Failover With Fast-Start Failover, standby can automatically become the primary.
- Backup Offloading Backups can be done on the standby, preserving performance on the primary.
🧠 When to Use Data Guard?
Mission-critical systems needing zero or minimal data loss
Businesses with strict uptime requirements
Enterprises with disaster recovery policies
Scenarios needing read scalability or reporting on live data