[tor-dev] Uptime stats for "Tor user can access an otherwise-functional hidden service"?

[George Kadianakis]

Holmes Wilson <h at zbay.llc> writes:

> And I just saw today's blog post about the new status page. Congrats on launching this! Someone is reading my mind :) 
>

Hello Holmes,

glad you like the status page! It's indeed great!

> But is there any good source for historical data on incidents or re: the questions below? 
>

I don't think we have historical data about v3 downtimes unfortunately,
apart from the January event mentioned on status.torproject.org . 

We *have* developed tools to monitor the health of v3 onion services in
an attempt to weed down reachability issues [0] but we mainly used the
tool to find specific bugs, and not as a downtime scanner. That is, we
never performed truly long-term experiments with it, or hooked it to
some global dashboard.

> Also, is there currently some monitoring in place such that someone on the Tor team gets a phonecall or SMS alert if onion services seem to be globally down? Several projects I’ve been a part of over the years have benefitted immensely from this, using tools like PagerDuty, so I’m curious if Tor has something like this for onion services. 
>

We are currently not aware of any unresolved reachability issues with v3
onion services.

Fortunately, the onion community is pretty active so we usually become
aware of such issues pretty quickly if they appear on a widespread
scale. That said, I don't think getting alerted more quickly (via an
SMS) would be a bad idea.

Regarding your question: 

> 2. What percentage of attempts by a user attempting to connect to a
> onion service are successful, assuming no successful censorship of the
> user’s network?

I would say 100% of attempts modulo unknown reachability bugs. Even if
the client picks a bad path, and a circuit gets broken, the Tor client
should be smart enough to rebuild the circuit and retry the onion
connection.

As always, if you have encountered reachability issues, please do get in
touch with us (and also please provide some logs) so that we can look
this more deeply.

[0]: https://gitlab.torproject.org/tpo/core/tor/-/issues/28841

>
>> On May 5, 2021, at 3:27 PM, Holmes Wilson <h at zbay.llc> wrote:
>> 
>> Hi everyone,
>> 
>> I’m building a messaging app based on Tor v3 onion services and I’m wondering what kind of uptime expectations we should set with users and other stakeholders. 
>> 
>> Is there data over time on uptime for onion service functionality? That is, not for a particular onion service, but for something like, given that the user’s access to Tor is not being limited by their ISP, and given that the onion service is fully operational, whether a Tor user can reach the onion service?
>> 
>> Some more concrete versions of this question are: 
>> 
>> 1. For what percentage of time over a given time period (say the past 3 years) are there no known network-wide problems affecting onion services?
>> 2. What percentage of attempts by a user attempting to connect to a onion service are successful, assuming no successful censorship of the user’s network?
>> 3. Is there some incident log somewhere of problems that affected onion services network wide that includes how long these problems persisted for? (I don’t see any onion service outage notes in this document, though I seem to remember there was an issue a few months back? https://metrics.torproject.org/news.html <https://metrics.torproject.org/news.html>)  
>> 
>> I see there’s uptime data for various relays, but I’m not sure how to translate this into a meaningful answer to the two above questions. Are there any good answers to these questions out there in the wild? Even approximate answers or lower bounds for uptime are fine and super helpful!  
>> 
>> Thanks!!!
>> Holmes
>
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