NGINX Cookbook, 3rd Edition

Chapter 4. Massively Scalable Content Caching

4.0 Introduction

Caching accelerates content serving by storing responses to be served again in the future. By serving from its cache, NGINX reduces load on upstream servers by offloading them of expensive, repetitive work. Caching increases performance and reduces load, meaning you can serve faster with fewer resources. Caching also reduces the time and bandwidth it takes to serve resources.

The scaling and distribution of caching servers in strategic locations can have a dramatic effect on user experience. It’s optimal to host content close to the consumer for the best performance. You can also cache your content close to your users. This is the pattern of content delivery networks, or CDNs. With NGINX you’re able to cache your content wherever you can place an NGINX server, effectively enabling you to create your own CDN. With NGINX caching, you’re also able to passively cache and serve cached responses in the event of an upstream failure. Caching features are only available within the http context. This chapter will cover NGINX’s caching and content delivery capabilities.

4.1 Caching Zones

Problem

You need to cache content and need to define where the cache is stored.

Solution

Use the proxy_cache_path directive to define shared memory-cache zones and a location for the content:

proxy_cache_path /var/nginx/cache 
                 keys_zone=main_content:60m 
                 levels=1:2 
                 inactive=3h 
                 max_size=20g
                 min_free=500m;
proxy_cache CACHE;

The ...