A non-general solution that might work for most of us is often goes by the name "shopper prioritization". Basically if you have a site that does lots of proces

A non-general solution that might work for most of us is often goes by the name "shopper prioritization". Basically if you have a site that does lots of processing (search, orders, etc) then a pretty effective strategy is often to show a generic static "down for maintenance, try again" page. This requires vastly fewer resources to serve since the page can be sitting in web server ram and doesn't result in rpc calls throughout the whole stack. You can also do something like prioritize logged in users over casual browsers. Since most http clients are smart clients you can even do some stuff with rngs and timeouts to selectively let people who are willing to wait around back into the site. Of course if you're an ad-tech company it's likely that serving an error is about as fast as serving something successfully.