[tor-bugs] #4483 [Tor Client]: If k of n authorities are down, k/n bootstrapping clients are delayed for minutes

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#4483: If k of n authorities are down, k/n bootstrapping clients are delayed for
minutes
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 Reporter:  arma                                                 |          Owner:                    
     Type:  defect                                               |         Status:  new               
 Priority:  normal                                               |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor Client                                           |        Version:                    
 Keywords:  performance bootstrap dos-resistance needs-proposal  |         Parent:  #2664             
   Points:                                                       |   Actualpoints:                    
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Comment(by mikeperry):

 Replying to [comment:7 arma]:
 > I had been imagining a design where we launch a further consensus fetch
 request every 5 seconds if the current one(s) haven't established a
 connection; but we don't hang up on the earlier ones until a much larger
 timeout. That way in the good case we don't make any more connections than
 now, but we failover much faster.

 But in the bad case where something like the #2664 crash, a dirauth
 censorship event, or a #3023-related circuit-based attack destroys dirauth
 reachability, new clients will still have to wait up to 5*N seconds before
 even attempting a dir mirror. Since for some reason we want to keep adding
 new dirauths, we'll soon be back up in the O(minutes) delay range with
 this plan in these circumstances. It might get even worse than that, if a
 large number of our #572 fallback dir mirrors end up unreachable.

 According to
 http://petsymposium.org/2012/papers/hotpets12-1-usability.pdf, even 30
 seconds of browser launch delay is enough time for 40% of the population
 to either give up or to assume magic has happened and Tor is already
 working somehow, even *with* progress bar activity...

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4483#comment:8>
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