Even though we only moved a short while ago to a new server we again migrated to a bigger server to avoid performance bottlenecks. We now moved from a virtual host to a relatively strong root server and have done some load tests which have indicate that this server should perform much better.
We also spend some time in performance optimization of the server, so this one is not only bigger but also better tuned. One of the things we did was switching from mpm-prefork to mpm-worker for the Apache 2 HTTP server. We also learned a lot about the pagespeed Apache 2 module.
We also moved our blog URL to http://blog.vogella.com and our training offering to http://training.vogella.com, this allows us to move these PHP based sites transparently to a separate server if required in the future.
Let us know if you see any issues. Many thanks to Markus Kuppe who did the majority of the work and performance optimization.
Lars on behalf of the vogella team