Unlike other cloud systems, for email there doesn't seem to be any additional complexities, any dieconomies at scale, no? You could in theory run 100,000 domains as 100,000 separate email services. It's not like social media where everybody is looking at and interacting with everybody's posts. And the email algorithm is well established, it's definitely easier than, say, settling financial transactions.

>Does having 400M users and 1B emails per day factor into your forgiveness?

No.

Because of the infinite resources premise and because there exist email services of that scale that are reliable. Email is not an unsolved problem.

The rest of your comment does not make much sense to me ...

When Microsoft has an outage it tends to be global. They don’t seem to learn institutionally how fault tolerance should work across a planet. All else- I wait for the postmortem to critiq

I don't have very much forgiveness, perhaps only for those junior engineers tending the beast they grew, and which now has indigestion. No-doubt there are all the usual machinations of large corporations at work. Tech companies are no better (in some ways worse) than "normal" companies, because of the invisible complexity of software. Brooks, Ousterhout, and Stroustrup were not fools. But MS run a service, they get freedom to choose how it is engineered internally so long as it continues to present a service interface to the users/client apps/other internal and external services. This is an incredible level of freedom to choose what you engineer for. MS always had the ambition to serve the world with this service. It doesn't seem like they engineered accordingly. It's easy to knock them, but I think they must have made some significant wrong choices.

I'll spare readers the full anecdote, but I worked for the company running the largest mail service in the southern hemisphere, and at the same time a few of the large mail services in the northern hemisphere in the 1990s. We met with the Exchange team who wanted us to adopt their product. Where we could run a given service on 2-3 servers, Exchange sized by MS required 300 of them for just 1 of our countries. Fortunately our cash constraints prevented us going down that road. They offered the license for free and exerted pressure on the C-level, as you can imagine there were heated conversations and some choice language between mgmt and engineering on this topic.

No, and I've been discussing this with a friend today.

Internal software goes through rigorous change control, change windows, change freezes around key business dates, etc to minimize risk.

Then you sign up for some SaaS and they blow out email (which aside from security needs 0 updates lets be honest) midweek, mid business day without warning or reason.

>1B emails per day

Jesus, make sure you stay away from signal processing if this trickle of data scares you

Just for a sense of scale, on a single CPU core that is something like 1M instructions per email. ONE CPU CORE.

They could've split it into smaller e-mail services in stead of designing one monolith for the planet.

I mean it's e-mail.