Carbon Copy Cloner is worth 12 stars out of 10 for a Mac OS X application. After a rebuild of the OS on our XServe (that powers this blog and Feed2JS), our temporary solution was to build the OS on an external Firewire drive loaned by a helpful Apple engineer who trouble shooted our server issues.
Since we are running smoothly, and Al needs his drive back, CCC made creating a local OS a snap.
Our XServe has two internal drives, one with most of the content, the other with the OS. The advice was to move all data off of the Volume that houses the OS, including the web directory (already done), the QuickTime streaming movies directory, and the location of the mysql database files (that required command line creating a symbolic link so the files could be found on the secondary drive.)
So it was time to put a clean OS back on the internal drive. Since the system hardly needed a full 60 Gb, I partitioned it generously in half (use the blank half for something else later), and used Carbon Copy Cloner to copy the full volume from the external drive to the new clean one. The clone was done by the time I had refilled my coffee and answered a phone call.
Reboot, and the new system was live. I can see cloning on a regular basis from now on.