[tor-relays] A bit more evidence on circuit creation storms

[Andreas Krey]

On Thu, 29 Aug 2013 19:35:37 +0000, Gordon Morehouse wrote:
...
> Aug 29 18:19:14.000 [notice] Your network connection speed appears to
> have changed. Resetting timeout to 60s after 18 timeouts and 172
> buildtimes.

Random data point: I had these yesterday on a VPS-based relay.

> My main question:  How do circuit creation requests on one's Tor relay
> cause load on one's network infrastructure?  Is it DNS requests?  Is
> it TCP connection state entries?  It's not bandwidth, we observed that
> above, and my router can handle far faster pipes than the one it's on
> currently.  The DNS failing is a sign that the router is under severe
> stress.

Possibly your uplink is full (supposing you're on some DSL), and is
starting to build up ping time; then DNS requests to the outside can
start to timeout.

Andreas

-- 
"Totally trivial. Famous last words."
From: Linus Torvalds <torvalds@*.org>
Date: Fri, 22 Jan 2010 07:29:21 -0800