[tor-relays] Tor crashes frequently on fast relay

Random Tor Node Operator tor at unterderbruecke.de
Wed Sep 11 08:05:52 UTC 2013


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Hello everybody,

since this botnet started flooding Tor, my Tor relay Bazinga
($196832C61F30E9D6D179393C9AED4E47FD29796B) has been experiencing some
issues.

Previously, it was relaying 100 Mbit/s for a few months without problem.
When the botnet came along, at first the throughput dropped to about
30 Mbit/s and Tor kept spamming "Your CPU is too slow" and crashed
every hour or so. I set RelayBandwidthRate to 20 Mbit/s which reduced
the crash frequency.

Then, 0.2.4.17-rc was released and I lifted RelayBandwidthRate back to
100 Mbit/s. At first it was running fine, but then the crashes came back.

This is from yesterday and the day before:

$ sudo grep -i interrupt /var/log/tor/log.1
Sep 10 08:59:40.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 10:01:45.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 11:04:50.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 12:49:56.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 13:51:01.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 15:22:18.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 16:07:27.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 10 18:56:03.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.

$ sudo zcat /var/log/tor/log.2.gz|grep -i interrupt
Sep 09 06:51:20.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 07:54:30.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 08:48:36.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 09:51:56.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 10:20:01.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 10:49:06.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 13:03:26.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 13:26:40.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 13:50:47.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 14:02:54.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 14:26:06.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 14:42:11.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 14:52:17.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 15:08:31.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 15:21:37.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 15:31:27.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 15:44:32.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 15:53:38.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:02:45.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:08:50.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:16:56.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:24:04.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:34:10.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:48:20.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 16:55:25.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 17:02:30.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 17:21:39.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 17:35:45.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 18:51:51.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 19:14:02.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 19:30:10.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 19:50:16.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 20:06:23.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 20:49:52.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 21:13:00.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 21:51:06.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.
Sep 09 22:54:22.000 [notice] Interrupt: we have stopped accepting new
connections, and will shut down in 30 seconds. Interrupt again to exit
now.

It is a VPS on a Xen hypervisor with
3x Intel(R) Xeon(R) CPU L5630 @ 2.13GHz and 2 GB RAM

According to htop, tor currently uses about 105% CPU and 350 MB RAM.
It was around the same CPU and RAM consumption while it was happily
relaying 100 Mbit/s.

At first I was suspecting the hoster to have reduced CPU resources or
so, but they said they didn't change anything, including no
virtualization parameters.

Any help would be appreciated.

- --RTNO
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