If you only have 20 guys and a corrupted filesystem is one of your potential problems, you're doing it wrong. That's why people have switched to cloud services - You pay for the ability to flatten your systems, and if you've not architected with the ability to flatten your systems, you're gonna be SOL in those situations.
Ultimately, you're resilient for what you prepare for. There's a lot of tradeoffs in spend. I get that that's an example and probably not a real pressing concern, but the point is: You shouldn't have everyone trained in everything. You should have escalation paths for everything non-obvious. You should also train your people better.
Ultimately, you're resilient for what you prepare for. There's a lot of tradeoffs in spend. I get that that's an example and probably not a real pressing concern, but the point is: You shouldn't have everyone trained in everything. You should have escalation paths for everything non-obvious. You should also train your people better.