[tor-dev] Raising AuthDirMaxServersPerAddr to 4?

[teor]

Hi all,

This is an email about an alternative proposal:

Let's deploy sbws to some more bandwidth authorities.

>> Do we have funding to continue to improve the bandwidth measurement
>> infrastructure? Or to maintain it?
>> 
>> If we don't have any grants in the pipeline, now would be a good time to
>> start some.
> 
> Agreed.
> 
> sbws was always intended (as far as I recall) to be a bandaid to make
> the torflow approach more maintainable, while we continue to await
> research on better-but-still-workable approaches. I hear the NRL folks
> have another design they've been working on that sounds promising.

There were a bunch of bugs in sbws that seemed to be excluding some
relays. So we stopped deploying sbws to any more bandwidth authorities.

In March and April, I said that we should block further deployments.
But I did some more analysis today, and I don't think those bugs are
actually blockers.

In #29710, it looked like sbws was missing about 1000 relays. But
it turns out that those relays aren't actually Running:
https://trac.torproject.org/projects/tor/ticket/29710#comment:13

In #30719, 90% of sbws measurement attempts fail. But these are
internal errors, not network errors. So it looks like it's a relay
selection bug in sbws:
https://trac.torproject.org/projects/tor/ticket/30719#comment:2

So I have an alternative proposal:

Let's deploy sbws to half the bandwidth authorities, wait 2 weeks, and
see if exit bandwidths improve.

We should measure the impact of this change using the tor-scaling
measurement criteria. (And we should make sure it doesn't conflict
with any other tor-scaling changes.)


If we do decide to change AuthDirMaxServersPerAddr, let's work out how
many new relays would be added to the consensus straight away. There
shouldn't be too many, but let's double-check.

T

--
teor
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