commit ac802316cb977e041d9e0b9cd3b40a4ae3f2e19a Author: Karsten Loesing karsten.loesing@gmx.net Date: Tue Jan 14 16:09:44 2020 +0100

Document known inaccuracy in onion service stats.

As discussed on #23367. --- src/main/resources/web/jsps/reproducible-metrics.jsp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main/resources/web/jsps/reproducible-metrics.jsp b/src/main/resources/web/jsps/reproducible-metrics.jsp index ed3ad4c..0058ab6 100644 --- a/src/main/resources/web/jsps/reproducible-metrics.jsp +++ b/src/main/resources/web/jsps/reproducible-metrics.jsp @@ -817,7 +817,8 @@ We need to subtract out the multiple counting of .onion addresses to come up wit the service stores <em>two</em> replicas per descriptor using different descriptor identifiers, both descriptor replicas get stored to <em>three</em> different onion-service directories each, and the service changes descriptor identifiers once every 24 hours which leads to <em>two</em> different descriptor identifiers per replica.</p>

<p>To be clear, this approximation is not entirely accurate. -For example, the two replicas or the descriptors with changed descriptor identifiers could have been stored to the same directory. +For example, the descriptors of roughly 1/24 of services are seen by 3 rather than 2 sets of onion-service directories, when a service changes descriptor identifiers once at the beginning of a relay's statistics interval and once again towards the end. +In some cases, the two replicas or the descriptors with changed descriptor identifiers could have been stored to the same directory. As another example, onion-service directories might have joined or left the network and other directories might have become responsible for storing a descriptor which also include that .onion address in their statistics. However, for the subsequent analysis, we assume that neither of these cases affects results substantially.</p>