A Content Delivery Network distributes your static content across geographically dispersed edge servers, reducing latency for users by serving content from the nearest location. For websites with a global audience, a CDN can reduce page load times by 50% or more for distant visitors.
CDN Integration and Cache Configuration
Integrating a CDN typically involves creating a CNAME record pointing your static content subdomain (e.g., cdn.example.com) to the CDN provider's edge network. Configure your application to serve static assets like images, CSS, JavaScript, and downloadable files from this CDN subdomain. The CDN pulls content from your origin server on the first request and caches it at the edge for subsequent requests.
Set appropriate Cache-Control and Expires headers on your origin server to control how long the CDN caches each type of content. Immutable assets like versioned JavaScript and CSS files can be cached indefinitely, while HTML pages should have shorter cache durations or be served directly from the origin. Use cache-busting techniques like filename versioning to force CDN cache invalidation when content changes.
Monitor your CDN's cache hit ratio and aim for 90% or higher. A low hit ratio indicates that content is being fetched from the origin too frequently, negating the CDN's benefits. Analyze cache misses to identify content that should be cacheable but has incorrect headers, and adjust your caching strategy accordingly to maximize offload from your origin server.