High availablity web hosting is built on a foundation of redundancy and scalability. Redundancy means having backup systems in place so that if one server or component fails, another takes over seamlessly, preventing any disruption to service. This redundancy extends across multiple data centers, often geographically dispersed, to further enhance reliability. Scalability allows your hosting environment to expand or contract based on demand, ensuring that your website can handle sudden spikes in traffic without performance degradation.