If you're in trouble and cannot find an answer to a question which goes beyond Stack Overflow...
If you have a not-so-usual solution for your problems but need to justify it to your boss...
If you like to think on your own rather than blindly follow "common wisdom" and "profound truth"...
...then 'No Bugs' Hare on Soft.ware might be the right place for you.
Your mileage may vary. Batteries not included

System Architecture (and it’s subfield Software Architecture) is a discipline which is surprisingly poorly covered. In a sense, it is still more an art than a science, and usually requires somebody intimately familiar with practical systems, to tell what’s to do and what’s to avoid when building a system.

IT Hares have lots of experience in both Software Architecture and more general System Architecture, and are trying to share their knowledge (and more importantly, their feelings) about them.

All Not so Common Wisdoms about System Architecture, page 5:

On Zero-Side-Effect Interactive Programming, Actors, and FSMs

Abstract: “WHY are functional programming languages not popular for interactive programming purposes?” and “WHAT we can do about it?”
Quote: “IMNSHO, deterministic Actors are the very best thing in existence for interactive programming, with lots of very practical benefits (from production post-mortem, to protection of in-memory state against server faults).”
[]

Unity 5 vs UE4 vs Photon vs DIY for MMO

Quote: “You can still use HLAPI despite its shortcomings”
Another Quote: “If you’re using one of the engines above (and not your own one), and your game requires Client-Driven Development Flow, you may want to start with a single-player Unity 5, or with a single-player UE4.”
[]

IDL: Encodings, Mappings, and Backward Compatibility

Quote: “Modifying generated code usually qualifies as a Really Bad Idea”
Another Quote: “How much can be gained by each of such specialized encodings – still depends on the game, but if you can try-and-test a dozen of different encodings within a few hours – it will usually allow you to learn quite a few things about your traffic (and to optimize things both visually and traffic-wise too).”
[]

MMOG. Point-to-Point Communications and non-blocking RPCs

Quote: “In other words, you can write your code ‘as if’ all-your-code-within-the-same-FSM executed within the same thread”
Another Quote: “As soon as we have these two parts of processing – we can say that our Server-to-Server communication is tolerant to all kinds of transient inter-server disconnects”
[]

MMOG: World States and Reducing Traffic

Quote: “In practice, for most classical RPGs you can get away with simulating each of your PCs and NPCs as a box (parallelepiped), or as prism (say, hexagonal or octagonal one)”
Another Quote: “Mathematically speaking, without Interest Management, the amount of data on our servers will need to send (to all players combined), is O(N^2). Interest Management reduces this number to O(N)”
[]

MMOG. RTT, Input Lag, and How to Mitigate Them

Quote: “For fast-paced games, there is one big problem with the flow shown on this diagram, and the name of the problem is “latency” (a.k.a. ‘input lag’)”
Another Quote: “No, better bandwidth doesn’t necessarily mean better latency”
[]

Asynchronous Processing for Finite State Machines/Actors: from plain event processing to Futures (with OO and Lambda Call Pyramids in between)

Quote: “With ‘callback pyramid’ it is not easy to express the concept of ‘wait for more than one thing to complete’ , which leads to unnecessary sequencing, adding to latencies (which may or may not be a problem for your purposes, but still a thing to keep in mind).”
Another Quote: “Don’t even think of converting all of your code to a so-called Continuation-Passing-Style”
[]