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)  

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