Comment 6 for bug 1498111

Tested this the other day when adding 150 compute nodes to an environment. The performance gains are noticeable and quite valuable. I've updated the patch that implements this change and modified it to use the "jsonfile" implementation of fact caching. In this way we add no new dependencies and still receive similar performance gains.

A deployer can choose to use redis but I don't think that it should be the default because the current implementation within Ansible does not allow for the use of user credentials or access to an external redis cluster. If that changes in future releases of Ansible I'd be happy to revisit the default settings.