They say you can’t be ‘up’ all the time, but when it comes to business-critical websites, you kind of have to be up… all the time. There is no foolproof way to avoid downtime completely, but knowing that it’s expensive - both in upfront costs (immediate costs of resource allocation and customer frustration) and in the longer term (revenue and loss of customers and their trust) - is ample incentive to avoid it at all costs.
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.