Zone redundancy is a crucial strategy in cloud computing that ensures services remain operational even if their primary availability zone (AZ) fails, as demonstrated by an incident in AWS' Sydney region where a zone outage disrupted access to services. This concept involves deploying infrastructure across multiple AZs to mitigate risks associated with localized failures due to power loss, flooding, or misconfiguration. Critical sectors like banking and healthcare particularly benefit from zone redundancy due to the high costs of downtime. While major cloud providers offer tools to facilitate zone redundancy, customers must implement and test these configurations, with platforms like Gremlin providing methods to simulate and assess the resilience of systems through controlled failure scenarios. By employing Gremlin's Scenarios, which include experiments like blackhole tests, users can validate the effectiveness of their redundancy measures without causing real-world disruptions.