Which component ensures that Zscaler's services remain resilient during updates?

The component that ensures Zscaler's services remain resilient during updates is the two app connectors. This redundancy is crucial for maintaining availability and reliability of services when one app connector might be undergoing maintenance or updates. By having two app connectors, Zscaler can ensure that traffic is seamlessly managed and routed even if one connector is not operational. This setup allows for continuous service delivery without interruption, enabling organizations to maintain access to Zscaler's security features without experiencing downtime.

In this context, the other components, although they contribute to service stability, do not specifically address the resilience during updates in the same way that multiple app connectors do. The load balancing feature is mainly focused on distributing traffic efficiently, while the data caching service enhances performance by storing data for quick access. The failover mechanism is vital for disaster recovery scenarios, but the specific focus on maintaining resilience during planned updates, such as software upgrades, is best supported by the use of dual app connectors.