What is High Availability?
High Availability (HA) ensures that your database system remains available even if some components fail. It’s a critical aspect of data protection and business continuity.
It's about minimizing downtime and ensuring continuous operation.
Key Concepts
- Redundancy: Having multiple components to handle requests.
- Failover: Automatically switching to a backup component when the primary fails.
- Load Balancing: Distributing traffic across multiple servers.
- Monitoring & Alerting: Tracking system health and responding to alerts.
Database Replication
Database replication is a key technique. It creates copies of your database – primary and secondary - so that if the primary fails, the secondary can take over.
Different replication methods include synchronous, asynchronous, and master-slave replication.
Active/Passive Architecture
In an active/passive architecture, a standby database server is running and ready to take over if the primary fails. This is a good starting point for less critical applications.
Service Discovery and Clustering
Service discovery allows different components to locate and connect to each other, facilitating complex setups
Monitoring & Alerting Tools
Tools like Nagios, Zabbix, and Prometheus are critical for monitoring server health. Set up alerts for critical thresholds.
Conclusion
Implementing HA is a complex process, but the benefits are significant.