Re:PID Controller for controlling the number of servers in a...
by viraptor on Sunday July 04, 2021 @11:36PM
(#27734437)
> I'm curious if there exists something intelligent enough to be able to rely on it for a large-scale deployment without human oversight?
I think without a context that's a no. Some systems will want good throughput, some want low latency and require pre-scaling on some cues (time of day, day of week), some want minimal cost but do want to allow bigger bursts for a max of N minutes, etc.
Any intelligent scaling without human oversight has a good chance of either burning your money or not optimising for what you care about.
I'm curious if there exists something intelligent enough to be able to rely on it for a large-scale deployment without human oversight? In general, I would think dead simple and manually controllable is a feature in the context of expenditure.
> Replacing PID with moving horizon estimator allowed me to cut time from startup until stable temperature by at least half and eliminate any measurable over or undershoots.
I'm familiar with PID controllers, but haven't used MHE before. The formulas look really similar at first glance to me. Three terms and three weights? Is a slow PID controller due to poor tuning, or is MHE intrinsically better? What is the reason that MHE would adapt more quickly with less overshoot than PID? MHE appears to be three integrals instead of one, but I don't see immediately why that would be better, is there an intuitive and/or fundamental reason?