On Fri, Aug 30, 2019 at 05:52:22PM +1000, teor wrote:
The default value for AuthDirFastGuarantee is still 100 KB. [...] 6/9 authorities use measured bandwidth, rather than reported bandwidth. So your relay won't get Fast unless it is measured by the bandwidth authorities, faster than 100 KB.
Right, it's this last part that's critical here. Directory authorities that do their own "bandwidth authority" measurements use their bwauth numbers rather than the self-reported numbers in the relay descriptor, for deciding whether to assign flags.
If you go to the very bottom of https://consensus-health.torproject.org/#relayinfo and put in this relay nickname or fingerprint, you'll see that 4 directory authorities -- the ones not running bandwidth authorities -- look at the self-reported number, and give the relay the Fast flag. But 5 of them, which are running bwauths, use their own numbers, which put the relay below the threshold. And since 5 is a majority of 9, their choice wins.
Hope that makes sense, --Roger