[swalsh]

And this is why Revert first, continuous deployment with feature toggles is the most stable way to run production. Deploy the new stuff, add some feature toggles. If the last version is stable, and your code is easy to revert, then you don't have to worry about downtime. If you're doing a major deploy, you can use the feature toggle to slowly turn it on (or off) and even use it test your new code directly in production (the systems I've used in the past allowed a developer to specify a feature toggle to be on for just their session). Databases can be tricky to toggle, but you have to build that into your design.