[tor-relays] Yet another underpowered relay?

Zack Weinberg zackw at cmu.edu
Mon Jul 22 17:26:22 UTC 2013

Make sure you have the most recent OpenSSL library, with the
ec_nistp_64_gcc_128 optimizations enabled.  (Tor will print a big
nasty warning on startup if the library is new enough but the
optimizations aren't available.)

You may get better utilization out of your CPU by running multiple tor
daemons (try 4 to start) each with MaxCPUs=1 and bandwidth cap set to
1/N of the total available.  They each have to be configured to use a
distinct ORPort and state directory, and should all be tagged as the
same family.


On Mon, Jul 22, 2013 at 1:08 PM, Logforme <m7527 at abc.se> wrote:
> I recently upgraded from an adsl line to a 100mbit fiber connection.
> Naturally I want to use most of this new bandwidth for my non-exit tor
> relay. However, I run into messages like these:
> Jul 22 17:40:26.000 [warn] Your computer is too slow to handle this many
> circuit creation requests! Please consider using the MaxAdvertisedBandwidth
> config option or choosing a more restricted exit policy. [665 similar
> message(s) suppressed in last 60 seconds]
> Jul 22 17:40:26.000 [warn] Failed to hand off onionskin. Closing. [1509
> similar message(s) suppressed in last 21600 seconds]
> Relay fingerprint: BE71 DC9D A443 5855 FAE1 E369 7080 1A60 0D51 3684
> Relevant torrc settings:
> BandwidthRate 10 MB
> BandwidthBurst 10 MB
> NumCPUs 2
> I did some research and came up with the following things to try:
> Set "MaxAdvertisedBandwidth x MB"
> Set "MaxOnionsPending 250"
> Get a faster computer / Get a computer with AES-NI
> I tried setting "MaxAdvertisedBandwidth 9 MB" for a few days which didn't
> seem to do much difference. This is only a 1MB reduction from the 10MB i use
> as a hard limit. Too little? Must I wait longer for the change to get spread
> around?
> Setting "MaxOnionsPending 250" seem to have reduced the number of log
> messages, but not eliminated them.
> The computer is somewhat dated but not ancient: Intel(R) Core(TM) i7 CPU 930
> @ 2.80GHz, 4 cores with HT, 6GB mem. I feel it should be able to handle a 80
> mbit bandwidth but have no hard data to support this.
> Looking at htop tor uses 2 cores. One core is constantly at around 90% (when
> all the 80 mbit bandwidth is used). The second core is hardly used.
> Since the relay can handle 80mbit (and higher) without messages I assume the
> problems only occur when the number of circuits get very high.
> Questions:
> What value should I set for MaxAdvertisedBandwidth?
> What other torrc settings could improve the situation?
> Am I wrong in thinking my cpu should be able to handle 80 mbit?
> Would upgrading to help?
> Weird sidenote: If I start iftop the first core drops to around 40-50%. Stop
> iftop and it jumps back to 90%. No change in traffic. What could that mean?
> _______________________________________________
> tor-relays mailing list
> tor-relays at lists.torproject.org
> https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays

More information about the tor-relays mailing list