4 ms·

> The underlying insight is that rates matter. If a system can handle 100 events a second, then 99 events per second everything is fine and 101 events per secon

• roenxi 5y ago
  If you want to maintain 99.99989% uptime or are about to spend $10 million, yes. If you want the cheap option then measure (arrival rate / service rate) and try to keep that below 80%. Then if that doesn't work adjust accordingly. That isn't really queue theory because it doesn't consider variance and requires effectively no knowledge of literature, what rho means or why people use M/M/1 queues as a default. Don't have to spell Poisson. But it will usually get you to where you want to be. Most of the time feeling it out in production is a lot cheaper than keeping an in house specialist. If it isn't then sure, maintain a specialist to monitor the situation. It is a relatively rare role though.
  • taneq 5y ago
    There's another advantage to feeling it out in production - you're measuring the actual system, not your theoretical model of the system, so all the extra things you've forgotten are automatically included (assuming you measure the right things, of course!) And keeping your safety margins nice and wide isn't just inefficiency. It's also building in resilience for when something unexpected does happen. Yes, if you need your six-nines performance on a 1% margin then maybe you should try to optimize this to the nth degree, but realistically almost none of us have to sail that close to the wind.