VMOD in the spotlight: accept

Varnish offers a multitude of modules that extend standard VCL capabilities for specific use cases and improve the overall user experience. These modules are written in C, and we call them VMODs for short. You can see the full list here.

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4/28/21 11:23 AM
by Thijs Feryn

The difference between Hit-for-Miss and Hit-for-Pass

A few weeks ago, I wrote and post introducing the concept of Hit-for-Miss and I received a few questions about it because "Hit-for-Pass" is much more common on the interwebz, and it looks like it could do something similar, and I completely omitted it last time. What's up with that?

Let's embark on a short chronological journey explaining how HfM and HfP (as the cool kids call them) came to be, how they are different and why you should care.

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12/4/20 11:15 AM
by Guillaume Quintard

5 Don'ts When Caching with Varnish

Over time, the most popular content we’ve created relates to hands-on Varnish use and relevant dos and don’ts. Naturally, we continue to create more content about this because our raison d’être is to help Varnish users get the maximum performance and efficiency they can from their Varnish setups.

Let’s get down to business.

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10/19/20 6:57 PM
by Arianna Aondio

Hit-for-Miss AND why a NULL TTL is bad for you

Varnish is a caching server, and a great one at that, that much we already know. But what about the content you don't want to cache? For example, those shopping cart requests and other completely uncacheable API calls?

We can of course handle it, but we've got to be wary of the sirens of the cargo cult because you will often see something like this on the internet:

sub vcl_backend_response {
# check if the backend response header named
# "cache-control" contains the word "private"
if (beresp.http.cache-control ~ "private") {
# if so, don't cache by limiting the Time-To-Live
# period to 0 second
set beresp.ttl = 0s;
}
}

This is both pretty intuitive, and also very wrong. In this post, we'll explore why it's a bad idea, how to do better, and along the way, we'll try to shine some light on a couple of lesser known features of Varnish.

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10/15/20 4:12 PM
by Guillaume Quintard

Varnish Software Blog

The Varnish blog is where our team writes about all things related to Varnish Cache and Varnish Software...or simply vents.

 

 
 

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