[tor-bugs] #17905 [Tor]: Consider removing fallback directory weights

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#17905: Consider removing fallback directory weights
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 Reporter:  teor                    |          Owner:
     Type:  enhancement             |         Status:  reopened
 Priority:  Medium                  |      Milestone:  Tor: 0.2.8.x-final
Component:  Tor                     |        Version:
 Severity:  Normal                  |     Resolution:
 Keywords:  must-fix-before-028-rc  |  Actual Points:  8 hours
Parent ID:  #17158                  |         Points:  small-remaining
 Reviewer:                          |        Sponsor:
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Changes (by teor):

 * points:   => small-remaining
 * actualpoints:   => 8 hours


Comment:

 Replying to [comment:7 teor]:
 > Replying to [comment:6 arma]:
 > > I think Sebastian and s7r make a good point that we should pick relays
 that are capable of serving the consensus to clients, and so long as all
 of the relays are above some minimum bar, things should work well enough.
 >
 > I propose that we weight each fallback directory "10.0", so each
 fallback directory is ten times more likely to be chosen than any
 authority. (The default weight of authorities is "1.0".)

 I also propose that we make the minimum consensus weight 3000. This is
 (nominally) 100 times the expected extra load of 30 kilobytes per second =
 50GB per month.

 In #17158, I've emailed operators of fallback candidates with weights
 30,000 and greater, and I'm considering contacting those between 3000 and
 30,000 if I need to make up numbers.

 I think this change is a good idea because equal weighting:
 * makes the security / privacy analysis easier,
 * makes for better load balancing as the list ages, consensus weights
 change, and relays go down, and
 * simplifies the script.
 There are also minor benefits for statistics collection.

 I'll submit the fix with #17158.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17905#comment:11>
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