Mark Delany <[email protected]> wrote: > > But in terms of thundering herds, it's still seem no worse than if none of > the stub > resolvers cached. > > However, I can see how if the choice is between stub caches which "smear" TTL > (regardless > of mechanism) and stubs which don't "smear", the smearers are probably a > little nicer to > recursive resolvers which incur high costs queuing duplicate queries.
Right. > But then I have to wonder, is there a fundamental reason why recursive > resolvers perform non-linearly as the arrival rate of identical queries > increases? It's the bimodal behaviour between cache hits and misses, and the higher the query rate the more queries arrive while the cache is being refilled. I think it only gets nonlinear if the recursive server's query deduplication is nonlinear. I was probably wrong to worry about thundering herds - I was thinking about them because I started wondering about synchronized cache expiry in a somewhat different context. Then I noticed that stub caches might stymie prefetching... Tony. -- f.anthony.n.finch <[email protected]> http://dotat.at/ Viking, North Utsire: Variable 3 or less, becoming southerly 4 or 5, occasionally 6 later in north. Slight, occasionally moderate later. Showers. Good. _______________________________________________ dns-operations mailing list [email protected] https://lists.dns-oarc.net/mailman/listinfo/dns-operations
