How long does it take you, to recover an arbitrary server, or duplicate an arbitrary running configuration to a new system? Especially in the latter case without a full-backup, which would contain a wrong IP Address, Hostname and other things and would therefore eventually break some things - and are storage-exhaustive.
Get into FAI - Fully Automatic Installation.
FAI http://www.informatik.uni-koeln.de/fai/) is a framework for completely automated installations - via LAN, CD or USB stick, as well as configuration management for running systems. The concept "Plan your installation, and FAi installs your plan" supports, but also requires building a well planned and documented infrastructure. Configuration properties can be defined into the smallest possible Detail, and then be arbitrarily combined - a great advantage in environments with many different system types, which at the same time share one or multiple common bases and settings. FAI makes it possible to install and change many different systems at the same time.
In addition to all these things, with the grml-live software, FAI can even be used to build live cd's/usb sticks. This talk will give an overview of the functionality and possibilities of FAI, including a comparison with the also renowned software for similar, but not completely the same tasks, Puppet - which can even be integrated into FAI.