Instruction: Discuss strategies to ensure a Node.js application remains available and performant under high load.
Context: This question evaluates the candidate's understanding of scalability and availability concepts, and their ability to apply them in Node.js applications.
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Firstly, Load Balancing plays a critical role. By distributing incoming traffic across multiple servers or instances, we mitigate the risk of overloading a single server. In my previous projects, I've utilized both DNS and hardware load balancers, but I've found NGINX to be particularly effective when used as a reverse proxy. This not only aids in handling high traffic but also in achieving fault tolerance.
Another essential strategy is the use of Clusters. Node.js operates on a single thread, which can become a bottleneck. Leveraging the Node.js cluster module allows the application to take full advantage of multi-core systems, spawning a cluster of Node.js processes. This way, if one process fails, others continue to serve requests, enhancing...