[tor-bugs] #16723 [Tor]: randomize HH:MM in AccountingStart for a more even distribution of hibernating relay resources

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#16723: randomize HH:MM in AccountingStart for a more even distribution of
hibernating relay resources
-----------------------------+-------------------------------
     Reporter:  cypherpunks  |      Owner:
         Type:  enhancement  |     Status:  needs_information
     Priority:  normal       |  Milestone:
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by cypherpunks):

 Replying to [comment:10 teor]:
 > If the estimate is inaccurate, why not try to fix the estimate, at least
 as a first step?

 I just assumed that having accurate estimates is harder.

 > Have we confirmed that the estimate is inaccurate on a consistent basis?

 Depends on what accuracy you are aiming at.
 Currently out of 59 relays 50 exhausted their relays >3hours before
 interval start time.


 > Given that the bandwidth authorities are currently thrashing about, that
 could be causing the inaccuracy at the moment.
 >
 > I agree that randomising the lower-order components of the period would
 mitigate the thundering herd wake issue, but 100/5000 relays is not really
 a herd.
 >
 > So we'd have to decide whether the unpredictable behaviour would be
 worthwhile, and outweigh the existing assumption of a 00:00 interval start
 time.
 >
 > When I configured hibernation, I depended on the fact that the
 changeover time was 00:00, as that was the time that the VPS' free quota
 was reset.
 >
 > Changing the behaviour for existing configs would be a really bad idea,
 if it led to people exceeding their quotas due to unpredictable interval
 start times, where those start times overlapped poorly with the charging
 intervals on the VPS.
 >
 > (For example, if 11:39 was chosen at random, I could have had almost two
 periods' worth of usage in the one charging period, if the wake time was
 late one day, and early the next. This would have been expensive for me.)


 I've no strong opinion how and if that behavior gets changed, we can also
 simply send an email to tor-relays to ask ops to changed their
 accountingstart time if they wish to distribute restarts more evenly.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16723#comment:11>
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