As you may know, part of my job consists of helping Varnish users, both customers and community users (join us on IRC!), often looking at their VCL and see if there's anything wrong. And sometimes, there is. After all, VCL is a programming language and mistakes happen. However, one point stands out as being badly understood, and I feel it deserves a short blog post to set the record straight.
This post was initially titled "Top 6 Varnish mistakes", to echo Espen's blog. Even though his material is three years old, the content is still relevant. Plus, there's a healthy colleague competition going on here, and I can't just mimic Espen if I hope to beat him, so I had to do something different.
Instead, I'm going to compete on brutality: this post isn't about explaining the most common mistakes, but rather the ones that can really kill your service, one way or another. I know it sounds a bit scary, and it is, but that's for your own good, really. So buckle up, and let's see what I have in my Little Shop of Errors.