Varnish sits in front of the web or application server and caches its output. This means that the logs of the web server no longer paint a complete picture of your site’s traffic. To get a complete view, logging on the edge is needed.

This is why we developed Varnishlog, a powertool to perform in-depth analysis of your requests, responses, backend fetches, backend health and caching behavior–so that you can generate actionable insights to improve performance, reliability, functionality and security.

In this week’s episode of Two-Minute Tech Tuesday, we'll talk about varnishncsa, a tool that you can use to produce web server logs in Varnish.

While we have spent some time explaining all the surprising things that the Varnish private CDN solution contains under the hood, an important factor in performance is being able to understand what’s going on under the hood one level deeper, at a more diagnostic level.

One aspect of Varnish that customers and enthusiasts most often ask questions about is how to make more effective use of Varnish’s powerful logging features. Logging and log management is important because your logs can be a real-time account of what is happening behind the scenes with your web traffic and transactions, resource performance, and much more. The detailed nature of logs lets you identify specific issues, anomalies or patterns and troubleshoot, sometimes getting to root causes of problems or seeing and stopping threats emerge before they can do any damage.