in Crash Course, Performance

Running vBulletin Cluster Using Varnish

Update (2011-02-16): If you’re interested in running Varnish with cPanel, UNIXY has created a cPanel Varnish plugin. Our Varnish VCL configuration performs much better than Litespeed. Read more about it here:

Update (2010-10-09): Should you be interested in a managed vBulletin dedicated server know that UNIXy has built a system that is ideal for those that want to run a lightening fast vBulletin forum. Visit the following product link:

Varnish is an excellent Web accelerator that can be made to proxy requests in and out of a cluster of somewhat more fully fledged Web servers like Apache or Litespeed. It has some great features like its compiled language, called VCL, and C-like programming API.

Large vBulletin deployments tend to be heavy on CPU and memory due to PHP script processing. For a large vBulletin forum, we recommend a cluster of 5 physical servers with three of those running Xen virtualization. One of those servers will be dedicated to the MySQL master database. Three to be setup as “headless” PHP nodes and Varnish load balancing and failover. And finally one as the NFS file store. The three headless servers need to run Varnish in their own VM and Litespeed or Apache in their own VM similarly.

The varnish backend director functionality makes it ideal to balance incoming traffic across all PHP headless nodes. It makes the configuration scalable and plug and play especially when needing to scale out within hours. The challenge in this setup is in making Varnish work correctly with vBulletin. Otherwise, session problems will occur.

We have a lot to share on this implementation so keep checking this blog as we will post it all. In the next installment, we’ll go through our deployment of a large vBulletin forum for a customer. In the mean time, feel free to get in touch should you have a question or comment. If you are interested in us helping you accelerate your server, we have a page explaining the different technologies we deploy on our clients’ dedicated servers. Read up here:

That’s all folks!