Episode 95: High Availability and System Resilience (Domain 3)

Security isn’t just about keeping attackers out—it’s also about keeping services running when they try to bring you down. In this episode, we examine high availability (HA) and resilience strategies that ensure critical systems continue operating during failures, attacks, or overload scenarios. Techniques like active-active clustering, redundant power supplies, geographic failover, and load-balanced application layers all work together to prevent downtime and maintain service continuity. We also discuss how system resilience includes not just technical redundancy, but organizational processes like playbooks, fault tolerance policies, and human escalation paths. A highly available system should fail gracefully, with components recovering automatically or falling back to standby systems with minimal delay. Security without availability undermines business continuity—and availability without security creates opportunity for abuse. The best designs deliver both, ensuring reliability under stress.