Varnish High Availability (VHA) is a high-performance content replicator for Varnish Plus. Using VHA with a group of Varnish Plus servers ensures that the cached objects will be efficiently replicated between caches when first fetched from the backend. This both provides higher performance to the client, and minimizes backend traffic.
This post was written by Varnish Software's Denis Brækhus and originally published on API.Report on 8 February 2016.
When an API is born, its purpose in life might be very well-defined and the expected usage seem limited. The creators of the API solve a particular problem, and they do it in a good enough way to handle the initial volume of calls. Maybe the API is designed to scale given a certain projected usage increase. At this point, performance does not seem like an important consideration.
Update (June 2017)
Some of the content in this post is outdated. We recommend that you read up on our Let's Encrypt with Hitch and Varnish tutorial instead.
"Let’s Encrypt is a new Certificate Authority: It’s free, automated, and open". Using Let's Encrypt, anyone with ownership of a domain name can acquire a TLS certificate for their own personal use.