This is a child ticket from legacy/trac#33018. The idea here is that even if we hit the global write limit (bw), we should not return 503 code but rather answer another directory authority. Dirauth _must_ be able to talk to each other at all time regardless of the bandwidth state. Setting 043 milestone because this should be considered a bug and could even be considered for backport since dirauth are suffering from this at the moment.