NGINX Cookbook

Chapter 4. Massively Scalable Content Caching

4.0 Introduction

Caching accelerates content serving by storing request responses to be served again in the future. Content caching reduces load to upstream servers, caching the full response rather than running computations and queries again for the same request. Caching increases performance and reduces load, meaning you can serve faster with fewer 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.

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=CACHE:60m 
                 levels=1:2 
                 inactive=3h 
                 max_size=20g;
proxy_cache CACHE;

The cache definition example creates a directory for cached responses on the filesystem at /var/nginx/cache and creates a shared memory ...