running relay severely degrades network performance eventually
Hello list, every time I run a relay on a Comcast cable connection, after a while (a few hours to days) other network operations such as DNS lookups slow down to such an extent that the network becomes unusable. Unfortunately I don't know how to exactly pinpoint what the problem is, but found that the only reliable solution at such a point seems to be to reset the cable modem. Is that a known issue? Could you suggest how I can diagnose this more accurately? Thanks, nick
On Mon, Jan 21, 2013 at 04:31:01PM -0700, Nicolas Bock wrote:
every time I run a relay on a Comcast cable connection, after a while (a few hours to days) other network operations such as DNS lookups slow down to such an extent that the network becomes unusable. Unfortunately I don't know how to exactly pinpoint what the problem is, but found that the only reliable solution at such a point seems to be to reset the cable modem.
Is that a known issue? Could you suggest how I can diagnose this more accurately?
Two likely possible causes: either your relay is using a lot of bandwidth and causing congestion, or your cable modem is doing NAT and the many active TCP connections from the relay overload the modem's feeble mind. Try reducing the maximum bandwidth in your torrc and see if that resolves the problem. To get closer to a root cause, I'd use mtr, http://en.wikipedia.org/wiki/MTR_%28software%29 , to compare performance during a "speedy" period and during a "slow" period. Specifically, I'd "mtr -u some-nearby-IP" and switch to "last" mode with the 'd' command, twice. This lets me see where in my pipeline the slowdown is likely occurring. If the location of the bottlenck changes over time as the visible performance gets worse, then there is a clue where the performance change is coming from. -andy
? I never wrote this, is some1 using my email?
On Mon, Jan 21, 2013 at 04:31:01PM -0700, Nicolas Bock wrote:
every time I run a relay on a Comcast cable connection, after a while (a few hours to days) other network operations such as DNS lookups slow down to such an extent that the network becomes unusable. Unfortunately I don't know how to exactly pinpoint what the problem is, but found that the only reliable solution at such a point seems to be to reset the cable modem.
Is that a known issue? Could you suggest how I can diagnose this more accurately?
Two likely possible causes: either your relay is using a lot of bandwidth and causing congestion, or your cable modem is doing NAT and the many active TCP connections from the relay overload the modem's feeble mind. Try reducing the maximum bandwidth in your torrc and see if that resolves the problem.
To get closer to a root cause, I'd use mtr, http://en.wikipedia.org/wiki/MTR_%28software%29 , to compare performance during a "speedy" period and during a "slow" period. Specifically, I'd "mtr -u some-nearby-IP" and switch to "last" mode with the 'd' command, twice. This lets me see where in my pipeline the slowdown is likely occurring. If the location of the bottlenck changes over time as the visible performance gets worse, then there is a clue where the performance change is coming from.
-andy _______________________________________________ tor-relays mailing list tor-relays@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
On Mon, 21 Jan 2013 16:31:01 -0700 Nicolas Bock <nicolasbock@gmail.com> wrote:
every time I run a relay on a Comcast cable connection, after a while (a few hours to days) other network operations such as DNS lookups slow down to such an extent that the network becomes unusable. Unfortunately I don't know how to exactly pinpoint what the problem is, but found that the only reliable solution at such a point seems to be to reset the cable modem.
Is that a known issue? Could you suggest how I can diagnose this more accurately?
The dd-wrt page has some hints that may apply if you have a router between your relay and Comcast cable. Specifically settings such as TCP timeout and Max Connections. I don't know if Tor already checks those limits and throttles itself to match, or what the recommended router settings are for Tor relays. http://www.dd-wrt.ca/wiki/index.php/Router_Slowdown
participants (4)
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Andy Isaacson -
caesars＠tormail.org -
k e bera -
Nicolas Bock