On the SitePoint PHP blog they've posted a new tutorial looking at the combination of Symfony applications (well, one specific one) and Vagrant to optimize it for the best performance possible.

In this short tutorial, we’ll set up Sulu, a new Symfony based CMS, and optimize it on a Vagrant environment. Why a dedicated tutorial handling this? Besides the fact that Sulu has a rather complex initialization procedure, it is based on Symfony which is infamously slow on virtual machines with shared filesystems, and thus needs additional optimizations post-install. The performance hacks in this post, while Sulu-specific, can be applied to any Symfony application to make it faster on Vagrant.

The rest of the post walks you through the steps to get the box set up and the Sulu application up and running:

• New Box and Folder Sharing
• App Type and Vagrant Boot (configuration)
• Installing Sulu

Then they get into the speed improvements and "hacks" to make the overall system perform better. They make updates to the log/cache directory fetching, moving the "vendors" folder into the VM (non-synced) and enabling the APC caching on autoloading. The tutorial also includes a few helpful troubleshooting tips of things to check if a problem does happen to pop up.