[tor-bugs] #8164 [Metrics Website]: Validate flag-thresholds in consensus-health checker

Tor Bug Tracker & Wiki blackhole at torproject.org
Tue Apr 9 01:55:35 UTC 2013


#8164: Validate flag-thresholds in consensus-health checker
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 Reporter:  karsten          |          Owner:  karsten          
     Type:  enhancement      |         Status:  needs_information
 Priority:  normal           |      Milestone:                   
Component:  Metrics Website  |        Version:                   
 Keywords:                   |         Parent:                   
   Points:                   |   Actualpoints:                   
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Changes (by karsten):

 * cc: mikeperry (added)


Comment:

 Updated the
 [https://trac.torproject.org/projects/tor/attachment/ticket/8164/flag-
 thresholds-2013-04-09.png graph] once more.  Finally, we have all nine
 authorities reporting their flag thresholds, with interesting results.  A
 few observations with respect to finding lower/upper bounds for what the
 consensus-health checker should consider normal:

  - The mean stable_uptime of most authorities is around 7.2 days (620000
 seconds), whereas turtle's mean stable_uptime is 17.6 days.  What's up
 with turtles, and should we still consider those values normal?  How about
 5 and 20 (or 10?) days as lower and upper bound to catch extreme values?

  - I can hardly see a stable state in stable_mtbf.  Without turtles, I'd
 say that gabelmoo, moria1, and dannenberg are heading somewhere, but that
 process takes very long, probably too long for continuous consensus-health
 warnings.  How about 1 second as lower bound and 3e+6 seconds (34.7 days)
 as upper bound to see what turtles is up to?

  - fast_speed looks quite stable, well, except for turtles.  I'd say 25
 and 75 kB/s would be good lower/upper bounds.  But what turtles sets there
 seems too low.

  - guard_wfu looks okay.  We could probably set a lower bound of 90 to
 learn about extremes (and 99.99 as upper bound, just to learn when
 authorities become too demanding).

  - guard_tk takes a while to get stable after authorities went down for
 some time (which is what I think was the case with dizum).  We could warn
 about values below 4e+05 seconds (4.6 days) and above 8e+05 seconds (9.3
 days).

  - guard_bw_inc_exits and guard_bw_exc_exits look quite stable, too.  But
 what is turtles doing there?  Without turtles, I'd say 1e+05 and 3e+05 are
 fine lower/upper bounds.

  - enough_mtbf looks like it's fine with a lower and upper bound of 1, so
 that we learn when it goes down to 0.

 Do these limits make any sense?  And what's the reason for turtles
 behaving different?

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8164#comment:8>
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