What does horizontal scaling mean in the context of Mule applications?

Horizontal scaling, in the context of Mule applications, refers to the practice of increasing the capacity of an application by adding more instances or nodes within a cluster or environment. This means that rather than resizing individual resources to handle higher loads (which is vertical scaling), additional resources are deployed to share the workload.

When you deploy the application across multiple CloudHub workers, each worker can process its own requests concurrently, allowing the application to handle more traffic and providing redundancy. This approach is particularly beneficial for applications that require high availability and robustness, as it distributes the load and minimizes the impact of any single point of failure.

In contrast, the other options focus on different aspects of resource management. Resizing a Mule application worker refers to vertical scaling, which involves altering the size of a single instance rather than increasing the number of instances. Increasing storage capacity pertains to resource management rather than scaling performance capabilities, and implementing caching mechanisms addresses performance optimization rather than scaling, since it operates within an existing architecture without adding more instances.