can't wait for the post mortem : o really wondering why there's an outage. I assume the SGX stuff quickly became a bottleneck, or the message forwarding server wasn't made to scale out very efficiently. In any case, they should have been able to have a very large queue in front of these components and just have a very slow system, probably something blew up due to the sudden peak of users.
https://twitter.com/signalapp/status/1350185818527211521