At what bandwidth threshold is being a dir mirror unwise?
Right now you opt not to advertise your dirport if your bandwidth rate is 50KB or less.
In legacy/trac#1338 (moved) there's a feisty discussion about whether we should make all relays dir mirrors. Or at least make all guards dir mirrors, to prepare for the glorious future when we use directory guards.
What sort of overhead do you get from being a dir mirror in practice? Will it change as we migrate from the v3 design to the microdescriptor design?
Bridges are dir mirrors no matter their bandwidth. The load on bridges would seem to be different than the load on public relays, since bridge load is a function of how many Tor clients are bridging through them. How can we compare?