[EdwardDiego]

> adding a replica to the in sync replica list take several hours if partition are 300GB

I'd be curious to hear more about this, because I run several topics with similar partition sizes, and haven't encountered several hours for one replica, and I've routinely shifted 350GB partition replicas as part of routine maintenance.

I have encountered 2 hours to restore a broker that was shut down improperly, but yeah, assuming your replica fetchers aren't throttled to shit, or your brokers aren't overloaded (what's the request handler avg idle? 20% or lower is time to add another broker, 10% is time to add another broker right now), that's really extreme.