[tor-bugs] #28042 [Core Tor/sbws]: Restrictions on the number of minimum measurements to include a relay in the bandwidth file give very few relays

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#28042: Restrictions on the number of minimum measurements to include a relay in
the bandwidth file give very few relays
---------------------------+-------------------------------------
 Reporter:  juga           |          Owner:  (none)
     Type:  defect         |         Status:  new
 Priority:  Medium         |      Milestone:  sbws 1.0 (MVP nice)
Component:  Core Tor/sbws  |        Version:
 Severity:  Normal         |     Resolution:
 Keywords:                 |  Actual Points:
Parent ID:                 |         Points:
 Reviewer:                 |        Sponsor:
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Comment (by teor):

 Replying to [ticket:28042 juga]:
 > In #27338##comment:6, teor suggested:
 >
 > > If any of these things are true, do not put the relay in the bandwidth
 file:
 > > * there are less than 2 sbws measured bandwidths
 > > * all the sbws measured bandwidths are within 24 hours of each other
 >
 > With these restrictions and the current data, the number of relays to be
 included in the bandwidth file is only 242.
 > Removing 1st restriction (ie, min num measurements: 1), there're 5209
 relays
 > Incrementing the number of hours between each other to 3d, doesn't give
 any relays
 > Decrementing the number of hours between each other to 12h, gives 302
 relays
 >
 > So:
 > 1. we should check prioritization, in case we're not doing it correctly,
 probably should open a new ticket for that

 If sbws' current prioritisation rule says "stop when there is 1
 measurement", we need to change it to "stop when there are 2 measurements
 that are at least 24 hours apart".

 > 2. do we want to publish bandwidth files with such a small number of
 relays?

 Torflow only publishes files when they contain 60% of the relays in the
 network. We should open a ticket for sbws to do the same thing. (If we
 want to change from 60%, we can do it in sbws 1.1.)

 https://gitweb.torproject.org/torflow.git/tree/NetworkScanners/BwAuthority/aggregate.py#n46

 > 3. should we eliminate the restriction of having at least 2 measured
 bandwidths?

 No, we should keep measuring until there are enough bandwidths. See 1.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28042#comment:2>
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