Multi-tier Informix HA architecture with RHEL app and database servers, featuring external users routing through Internet Gateway, WAF, and Firewall to a Load Balancer distributing traffic across three App Servers and a Background Task Server in the Application Zone. All application servers connect to an Informix Primary DB in the Data Zone, which replicates to a read-only Informix Replica DB for failover and reporting workloads. Monitoring continuously observes App Servers and the Primary DB to ensure availability and performance across the entire stack. This architecture demonstrates enterprise-grade separation of concerns with DMZ, internal firewall, and dedicated database zones, protecting sensitive data while maintaining high availability through primary-replica replication. Fork this diagram on Diagrams.so to customize firewall rules, add additional replicas, or integrate with your monitoring and alerting stack. Consider adding connection pooling at the application tier and automated failover scripts to maximize uptime during primary database failures.