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Varnish

May 21

The VCL Cookie Monster

This month's tip is more a theoretical exercise than anything else, just to show the power of VCL, and to explain a few regular expressions. I'm going to discuss VCL that deletes cookies.

April 22

Reusing backend connections to increase performance

Reusing connections between your Varnish instance and your backends (origins) is a good idea for multiple reasons. If your Varnish is on the same network as your backends and you're doing…

March 30

The benefits of using Varnish

At the core of Fastly is Varnish, an open source web accelerator that’s designed for high-performance content delivery. Varnish is the key to being able to accelerate dynamic content, APIs…

March 18

Common causes of a poor cache hit ratio and how to deal with them

The cache hit ratio (or hit ratio for short) is the ratio of hits to cacheable requests (hits and misses combined). There's also cache coverage, the ratio of cacheable requests to all…

January 27

Analyze your origin logs to get a higher cache efficiency

If you want to increase the efficiency of your Varnish (or Fastly) cache, you need to figure out what traffic is not cached. By definition, any traffic that reaches your origin is not cached…

December 15

Normalizing the Host Header

In the continued quest to increase cache hit ratios, the chant is: "Normalize, normalize, normalize." Less variation in your requests means you have a higher chance of getting hits. This…

November 11

Overriding Origin TTL in Varnish, or My Beginner's Mistake

A long time ago, I was helping out at a gaming conference where there was an intranet CMS using a Twitter search plugin. Unfortunately, the rather saturated Internet connection was slowing…

August 18

Best Practices for Using the Vary Header

Vary is one of the most powerful HTTP response headers. Used correctly, it can do wonderful things. Unfortunately, this header is frequently used incorrectly, which can lead to abysmal hit…