It's true that you can't get 100% uptime. And yes 99.999% is more of an SLA agreement/goal than a generally achievable metric. But Github aren't even managing

It's true that you can't get 100% uptime. And yes 99.999% is more of an SLA agreement/goal than a generally achievable metric. But Github aren't even managing two nines - they only have 98% uptime over the past month. That's bad for any service.