[tor-project] More resources required for Snowflake bridge

Arthur D. Edelstein arthuredelstein at gmail.com
Wed Mar 2 19:13:15 UTC 2022

Hi David,

Would you consider crowdfunding for donations? Al, Gus and Yan all got
big responses for their great tweets about Snowflake:


On Tue, Mar 1, 2022 at 3:27 PM David Fifield <david at bamsoftware.com> wrote:
> It has been great to see all the support and encouragement for people running Snowflake proxies. Thank you!
> But there is a problem: the Snowflake bridge (which all the temporary proxies forward their traffic to) is going as fast as can on its current hardware. The server is running close to 100% on all CPUs more or less constantly. As more people use Snowflake, they each get a smaller share of the limited available performance. The limited capacity of the bridge is the cause of the [recent slowness of Snowflake](https://www.reddit.com/r/TOR/comments/t49i14)—in the past 2 weeks it's gone [from 12,000 to 16,000 users, without a proportional increase in bandwidth](https://metrics.torproject.org/rs.html#details/5481936581E23D2D178105D44DB6915AB06BFB7F).*
> We've spent significant engineering resources already to make the most of the hardware, such as [load balancing multiple tor instances](https://github.com/net4people/bbs/issues/103) since a few weeks ago. This effort has roughly doubled the available bandwidth of the bridge, but it's still not enough. Demand will only continue to rise.
> The bridge needs to be moved to faster hardware. Its current hosting is free of charge, but is already on the highest-spec VPS configuration (8 CPUs, 16 GB). Switching to a server with, say, double the CPUs will have an immediate positive effect: the proof of that is that while we were installing the load balancing on the main bridge, I paid for an only slightly higher-spec server to handle Snowflake traffic during the upgrade, and during that week the bandwidth [immediately rose to higher than where it is now](https://github.com/net4people/bbs/issues/103#issuecomment-1033067920). I used Snowflake a lot during that week, and the difference was palpable.
> The minimum server required has something like 16 CPUs and 32 GB of RAM. meskio found some suitable [dedicated servers for about $200/month](https://lists.torproject.org/pipermail/anti-censorship-team/2022-February/000220.html) with unlimited bandwidth. (I estimate current needs are something like [100 TB/month of bandwidth](https://bugs.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/40095#note_2774428), of course expected to grow.)
> I'm writing this to make people aware that the current cause of poor Snowflake performance is known: it's limited CPU capacity at the bridge, not general Tor slowness or slowness of the temporary proxies. Solving the problem will cost a few hundred dollars per month, at least for the near future. I am open to suggestions about what to do. I promised myself I would not again get in the situation of paying out of pocket for important infrastructure. I've already contacted the Open Technology Fund about a possible rapid response grant, but have not gotten a response yet. I'm willing to continue administering the bridge, as I do now.
> * Since 2022-02-03, Tor Metrics graphs for the Snowflake bridge are 1/4 what they should be, until the fix for https://bugs.torproject.org/tpo/network-health/metrics/onionoo/40022 is deployed.
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