I've had more Microsoft Office 365 outages than Fastmail outages in the past 10+ years, and I'm sure Microsoft has a much deeper pocket than Fastmail.
Things break. More things will break in the future due to increased complexity, brittle network automation processes and poorly written code. You can mitigate failures to a certain extent, but you can't guarantee 100% uptime, even with a triple redundant system. Every business decision is a compromise among various constraints.
Things break. More things will break in the future due to increased complexity, brittle network automation processes and poorly written code. You can mitigate failures to a certain extent, but you can't guarantee 100% uptime, even with a triple redundant system. Every business decision is a compromise among various constraints.