Does traditional high availability incur more costs than resilience on the public cloud, and if so, why?

The assertion that traditional high availability incurs more costs than resilience in the public cloud can be supported by the fact that traditional high availability (HA) usually involves maintaining a redundant infrastructure. In this approach, an organization must have a passive virtual machine (VM) that remains on standby to take over in case the primary VM fails. This means that resources are effectively being wasted during normal operations since the standby system is not actively utilized but still generates costs.

In the cloud environment, resilience can be achieved through various design patterns that do not strictly rely on continuous active-passive configurations. Instead, resources can be scaled dynamically based on demand and only provisioned as necessary, leading to potential cost savings. The flexibility of the cloud allows businesses to implement strategies such as failover systems that do not necessitate a constant standby infrastructure, thus reducing ongoing expenses.

Understanding the distinction between these models highlights why traditional high availability can lead to higher costs, given that it requires constant resource allocation for the passive instance, whereas resilience strategies leverage the on-demand nature of cloud resources for more efficient and cost-effective operations.