I have a client that is hosting some business critical websites on a W2K3 server that is running IIS 6.0. The IIS server taps into a SQL server that is running on separate hardware. I've been asked to fingure out a way to enhance the redundancy of these server. I need the websites my client is hosting to still be up and runng even if one of the servers crash due to hardware failure. How do I go about doing this? A cluster? How do the big players do it?