Varnish makes your websites fly
….so goes the byline and frankly they’re not lying. I use varnish on atleast 8 websites that do over 200,000 impressions a day. The way it works is actually pretty simple and can be implemented using a plethora of other tools, only varnish does it much more efficiently. Varnish is primarily a website accelerator but it can be configured to work as a high availability load balancer (hell yeah it can beat the pants of any hardware HA load balancer if configured right on the right hardware it can probably do better than an H5). Some of the advertised features
A modern design
VCL – a very flexible configuration language
Load balancing with health checking of backends
Partial support for ESI
Graceful handling of “dead” backends
The important thing to know is that varnish can be easily dropped in into your cPanel or Plesk managed server and not cause havoc (unlike a lot of opcode caching solutions and other website speedup options). It can probably extend your servers capacity by atleast 50% and much more depending on what percentage of your content is static (images, videos for instance). I’ve used it on practically dead in the water servers, running 150+ sites with 140+ databases, the corresponding zones on named and email with spam/virus scanning for those 150+ sites all off of 2Gb RAM. Moved from 1.83seconds per kb to 0.01kbps, enuf said!!
So in case you’re looking to improve the user experience on your site without investing in improved hardware you should look at varnish as a solution. Also for much less than the cost of owning a hardware load balancer, or a slice of a shared load balancer for that matter, you can setup a software load balancer. Varnish works off one of your webservers alongside the webserver instance and takes the load off of your webserver(s) leaving it free to do the processing for more clients thus expanding your capacity without draining you at the bank.
Before upgrading hardware you’d probably do well to talk to us about setting up your server with Varnish. Please feel free to use the contact form or mail us on email@example.com