Looks like the status of the ticket has been updated to Resolved with the comment:
"Merged to master; if this helps us find a real bug, that bugfix will be backportable."
I'm now on v2.6.10 with Libevent 2.0.21-stable, OpenSSL 1.0.1p and Zlib 1.2.8 on Server 2012 R2 and I'm still seeing the warnings.
Brian
> Date: Thu, 6 Aug 2015 20:47:04 -0400
> From: arma@mit.edu
> To: tor-relays@lists.torproject.org
> Subject: Re: [tor-relays] Failure from drain-fd
>
> On Thu, Aug 06, 2015 at 05:13:45PM -0700, Brian Walker wrote:
> > Anybody know what this means? My logs are littered with it.
> >
> > Tor v2.6.9 with Libevent 2.0.21-stable, OpenSSL 1.0.1o and Zlib 1.2.8 on Windows Server 2012 R2.
> >
> > Aug 06 13:26:35.000 [warn] Failure from drain_fd [3892 similar message(s) suppressed in last 7200 seconds]
> > Aug 06 15:26:37.000 [warn] Failure from drain_fd [3526 similar message(s) suppressed in last 7200 seconds]
>
> Exciting.
>
> You might be among the few people running a recent Tor version on Windows
> as a relay. So thank you for reporting issues.
>
> I've filed
> https://trac.torproject.org/projects/tor/ticket/16741
> based on poking around the code a bit.
>
> Depending on how that ticket goes, we may then be in a better position
> to guess at what's going wrong for you. :)
>
> Thanks!
> --Roger
>
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