[tor-relays] minimal specifications for a non-exit relay?

[René Ladan]

Hi,

I was running a non-exit relay from my 50/5 Mb/s (more like 35/4 in
practice) home connection on a Raspberry Pi B (496 MB RAM, 700 MHz)
running FreeBSD using the following configuration:

Tor 0.2.4.24
% cat /usr/local/etc/tor/torrc
SocksPort 0
Log notice file /var/log/tor
ORPort 9001
ORPort [2001:980:d7ed:1:ba27:ebff:fe96:9eb2]:9001
Nickname ymkeo
RelayBandwidthRate 500 KB
RelayBandwidthBurst 500 KB
ContactInfo Rene <r.c.ladan at gmail.com>
DirPort 9030
ExitPolicy reject *:*
ExitPolicy reject6 *:*

This seemed to be fine until last night the socket connection pull ran
over, so I increased the value from 128 to 32768 (kern.ipc.somaxconn)
Things mostly seemed to be fine again until the kernel ran out of
resources later last night:

==> /var/log/tor <==
[warn] Your network connection speed appears to have changed. Resetting
timeout to 60s after 18 timeouts and 148 buildtimes.
...
Oct 29 00:28:44.000 [notice] Performing bandwidth self-test...done.

==> /var/log/messages <==
Oct 29 01:15:35 raspberry-pi kernel: [zone: mbuf_cluster]
kern.ipc.nmbclusters limit reached
Oct 29 01:15:35 raspberry-pi kernel: smsc0: warning: failed to create
new mbuf
Oct 29 01:16:30 raspberry-pi last message repeated 36 times
Oct 29 01:18:31 raspberry-pi last message repeated 1094 times
Oct 29 01:19:30 raspberry-pi last message repeated 450 times
Oct 29 01:19:30 raspberry-pi kernel: smsc0: warning: Failed to write
register 0x114
Oct 29 01:19:35 raspberry-pi kernel: smsc0: warning: failed to create
new mbuf
Oct 29 01:20:07 raspberry-pi last message repeated 157 times
Oct 29 01:20:50 raspberry-pi last message repeated 234 times
Oct 29 01:20:50 raspberry-pi kernel: [zone: mbuf_cluster]
kern.ipc.nmbclusters limit reached
Oct 29 01:20:52 raspberry-pi kernel: smsc0: warning: failed to create
new mbuf
Oct 29 01:21:37 raspberry-pi last message repeated 216 times
Oct 29 01:22:31 raspberry-pi last message repeated 558 times
Oct 29 01:22:31 raspberry-pi kernel: smsc0: warning: Failed to read
register 0x114
Oct 29 01:22:31 raspberry-pi kernel: smsc0: warning: MII is busy
Oct 29 01:22:31 raspberry-pi kernel: smsc0: warning: failed to create
new mbuf

==> /var/log/tor <==
Oct 29 01:22:32.000 [warn] Your system clock just jumped 332 seconds
forward; assuming established circuits no longer work.
Oct 29 01:22:32.000 [warn] Your system clock just jumped 332 seconds
forward; assuming established circuits no longer work.

==> /var/log/messages <==
Oct 29 01:23:12 raspberry-pi last message repeated 10 times
Oct 29 01:25:13 raspberry-pi last message repeated 855 times
Oct 29 01:25:51 raspberry-pi last message repeated 123 times
Oct 29 01:25:51 raspberry-pi kernel: [zone: mbuf_cluster]
kern.ipc.nmbclusters limit reached
Oct 29 01:25:51 raspberry-pi kernel: smsc0: warning: failed to create
new mbuf
Oct 29 01:26:21 raspberry-pi last message repeated 222 times
Oct 29 01:28:21 raspberry-pi last message repeated 279 times

Write failed: Broken pipe <-- local SSH connection dropped

It might be a matter of further tuning as ticket #9708 and the new
doc/TUNING suggest, once I log in at its console.

But if a Raspberry Pi is structurally underpowered (I don't imagine
relaying at fiber speed on them ;) ) shouldn't there be something on the
homepage or FAQ about this? I have seen at least one blog from someone
running a relay on a Raspberry Pi with Debian Linux.

Regards,
René