My understanding is that in practice, for very large shows, electronic musicians have fully redundant computer setups running in parallel and some hardware that will switch over instantly if one fails.

For example, here is one rig:

https://www.reddit.com/r/ableton/comments/7y2u3o/ableton_mai...

It uses a Radial SW8 to automatically switch between the redundant machines if one flakes out:

https://www.radialeng.com/product/sw8