[tor-relays] MaxAdvertisedBandwidth advice please

Andreas Krey a.krey at gmx.de
Fri Jan 4 20:47:15 UTC 2013

On Fri, 04 Jan 2013 13:36:20 +0000, mick wrote:
> But this morning I noticed that the new server had stopped and tor
> says in it's log "Your computer is too slow to handle this many circuit
> creation requests! Please consider using the MaxAdvertisedBandwidth
> config option or choosing a m ore restricted exit policy."
> I've never had the luxury of encountering this problem before,

I had. As it happened on a node with 50KB/s advertised bandwidth,
I assume that it's not actually the bandwidth, but a (mostly)
unrelated factor. My suspicion is that this happens when you
happen to become a crucial position for a hidden service.
(Or some rogue nodes are doing something strange.)

The problem is simply that the many circuit creation requests
cause a lot of CPU to be used, and the node can't keep up with
that. MaxAdvertisedBandwidth only very indirectly influences that.

> The manual entry for "MaxAdvertisedBandwidth" is not particularly
> clear because it does not specify whether the bytes|KB|MB|GB is per
> second or a maximum for some other period.

It isn't; one may deduce from the units of the referenced BandwidthRate
that MaxAdvertisedBandwidth is also per seconds.

> So my question is, what can colleages recommend as a suitable maximum
> rate which will allow my node to provide maximum utility to the tor
> network without falling over? 

As far as I can tell, tor is pretty much self-scaling in that regard,
but I only have nodes with a relatively low BandwidthRate (500k).

Do you have an explicit BandwidthRate set?


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

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