The significant majority of top-bandwidth Tor relay contributions originate from Europe—currently, 9 of the top 10 and 18 of the top 20 relays (Relay Search) This distribution appears to heavily favor European-based relays, significantly influencing traffic patterns.
I haven’t yet come across a comprehensive technical explanation for this phenomenon. Typical advice for boosting relay traffic includes ensuring relays have been running continuously over an extended period, verifying there’s no restrictive configuration limiting bandwidth, and confirming that relays have adequate CPU, RAM, file descriptors, local ports, and robust upstream network connectivity.
To help address this imbalance and add diversity, I recently deployed several 10 Gbps relays across various US locations. After around 90 days operating guard relays, I’m observing only about 10–20% bandwidth utilization at best and as low as 1–5% at worst. Consequently, 80–90% of the bandwidth I’m purchasing is effectively unused.
My observations over the past 90 days show that my relays located in US East receive roughly twice the traffic of those in US South and approximately four times that of US West. I suspect this disparity arises primarily from the superior network connectivity between US East and Europe.
Given these costs and inefficiencies, I’ve decided to stop running relays in US West and US South. As an experiment, I’m currently following this strategy: temporarily hosting relays in Europe to establish favorable bandwidth metrics before moving the relay keys back to US-based servers to see if higher traffic levels persist. Source: 2 relay per IP limit / how to use more bandwidth - #8 by lokodlare
Aside from these experimental strategies, I’m not aware of a better short-term solution. I’d be interested to hear if others have insights or experiences addressing this issue.
Attached a visual, using metricsport and prometheus and grafana showing the relay traffic averaged across servers for the last 24 hours since I started the experiment. I used ~90 day old relays to move into Europe to speed along the experiment.
Light blue going to the top is Amsterdam.
At the bottom are orange and green for Spain and Estonia. Seems Spain is consistently not doing well, but still early.
Top red and yellow and pink are Montreal, New Jersey, and Chicago.
Middle blue is New York and Middle purple is Texas.
