What is Varnish Cache
Varnish Cache is a web application accelerator also known as a caching HTTP reverse proxy. It is installed in front of any server that speaks HTTP and configured to cache the contents. The user puts in a request which first goes to the Varnish server and if no cache exists would pass straight though to the end server. If cache is held in Varnish memory the page is delivered substantially faster than having the server process everything again on disk. Varnish is a magnitude faster than relying on only Magento’s cache alone.
Varnish runs on a language called VCL (Varnish Configuration Language) which is then compiled into C-code.
The use of caching is widespread for example your browser may cache images to frequented sites. Varnish takes this a significant step further. When a request is made your server will look for the files which results in executing code and then returning the page back to the client. With varnish the client can revisit the page but it will be pulled from a full copy held in Varnish memory and immediately sent to the client. Not only is this significantly quicker but server load is much reduced.
Ecommerce:
Dx3Webs has always aimed to provide the hardware capable of supporting fast eCommerce solutions as we appreciate speed is very important in the world of on-line shopping. Customers are much more likely to browse and buy from a fast responsive shop. Conversion rates for sales can be directly related to your websites performance. Varnish helps give your site a performance increase complementing our hardware.
SEO:
In 2010 Google the largest search engine announced that page speed was a ranking factor. In July 2018 this will be extended in part when ranking pages in mobile searches. Speed really does matter.
Magento Extension:
Unlike many applications Varnish is easy to set up thanks to a number of Magento extensions capable of modifying your installation to work well together.
Varnish Cache is particularly effective for Magento sites with high traffic, taking a load off the server while speeding up the site for the end user. Add to that the SEO benefits and ease of use it is a product well worth considering.
Note: Magento 1 requires additional third party extensions to be implented by your developer. One of the significant changes for Magento 2 is fully integrated support for Varnish, if you are running a M2 site there are no additional extensions required. If you are on Magento 2 and wish Varnish enabled on your site please open a ticket.