[tor-bugs] #6752 [Tor]: TestingTorNetwork doesn't lower the dir fetch retry schedules

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#6752: TestingTorNetwork doesn't lower the dir fetch retry schedules
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 Reporter:  arma                      |          Owner:                    
     Type:  enhancement               |         Status:  new               
 Priority:  major                     |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                       |        Version:                    
 Keywords:  tor-client small-feature  |         Parent:  #7172             
   Points:                            |   Actualpoints:                    
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Comment(by robgjansen):

 Replying to [comment:16 nickm]:
 > Replying to [comment:15 karsten]:
 > > But before I write a patch, how would I reproduce the situation where
 clients don't bootstrap because of too high dir fetch retry schedules?  I
 tried a tiny-m1.large network with Tor 0.2.3.25, but scallion.log looks
 normal to me.  What log messages would I look for?  Or how would I change
 the configuration to reproduce the problem?
 >
 > I haven't run into this myself; maybe Rob would know?  Sometimes Chutney
 gets into a state where the network needs to be restarted after the
 authorities bootstrap.  You could try that; ping me if you need help.

 I asked Chris about this problem, as I believe he has more experience with
 it than I. Here is his response (Note that he was not using Shadow):
   We ran into that situation because of a slightly pathological case in
 our code. It happens frequently if descriptors get updated and pushed to
 the directories more frequently than the consensus period, which our code
 was doing. This significantly exacerbates the general problem by
 increasing the number of failures. I'm not sure if that's a viable test
 case though, since it's bad behavior (and we've changed our code to no
 longer do that).

   The problem may be more generally reproducible simply by starting the
 directories at exactly the same time you start the clients. The
 directories won't have completed the consensus negotiation (assuming a
 TestingTorNetwork interval of 5 minutes) by the time the clients get into
 the 60*5 back off period, so the clients will back off for 10 minutes.

   For this to work, you probably need 5 authoritative directories (to make
 sure their negotiations take a while).

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6752#comment:17>
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