The hedging strategies all seem to assume that latency for an object is an independent variable.

However, I would assume dependency?

Eg. if. a node holding a copy of the object is down and traffic needs to be re-routed to a slower node. Indifferently of how many requests I send, the latency will still be high?

(I am genuinly curious of this is the case)

S3 scale is quite massive with each object spread across a large number of nodes via erasure encoding.

So while you could get unlucky and routed to same bad node / bad rack, the reality is that it is quite unlikely.

And while the testing here is simulated, this is a technique that is used with success.

Source: working on these sort of systems

It’s not addressed directly but I do think the article implies you hope your request latencies are not correlated. It provides a strategy for helping to achieve that

> Try different endpoints. Depending on your setup, you may be able to hit different servers serving the same data. The less infrastructure they share with each other, the more likely it is that their latency won’t correlate.