In discussions with IT Pro’s at client sites, a few times I have seen them start off designing their farm to handle performance requirements for interstate users (e.g. Brisbane, Sydney, Melbourne) by having the core of the farm in Sydney, and then one web front end in Brisbane and another in Melbourne. Essentially an architecture that looks like this:
What’s the challenge here?
The challenge is that technically it won’t be supported by Microsoft, because what has essentially been created here is a stretched farm, that has a packet latency of > 1ms between the WFEs (W), App Servers (A) and SQL Servers (S). So why isn’t an environment like this supported? Because it will cause performance problems, as all the internal farm servers need to communicate with one another quickly. To get an idea for how significant the performance will be degraded, the typical statistic quoted is 50% per 1ms delay, ouch!