[tor-relays] Single IP multiple OR Ports

Moritz Bartl moritz at torservers.net
Mon Mar 3 23:40:10 UTC 2014

On 03/03/2014 11:53 PM, Felix wrote:
> In case there is a strong relay ie 1Gbit/s, enough cores and RAM
> so the HW is not limiting. Let's further assume only one IP. 
> Could a single Tor daemon on Debian be a bottle neck?
> If yes, could be more performance to start two (or more) daemons and
> bind the first OR Port to :443 and the second to :8080. Both at the same
> 'eth' interface?
> Both OR Ports are based on the same IP so they would be the same family
> member.

Yes, you do want to run multiple Tor processes on a high bandwidth
machine as Tor currently does not scale well across multiple CPU cores.
You will notice that you will hit a CPU limit at ~100 Mbps (or ~300-400
Mbps with a CPU that supports AES-NI crypto acceleration).

But, currently, you can only run two Tor process per IP address.

Relays in the same /16 IPv4 subnets are considered part of one family

Moritz Bartl

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