How accurate is Majordomo?

Does anyone know how accurate Majordomo’s data tracking is? I’ve been using it for the last 4 months to track data through my Turris router and am finding it reports volumes very, very different from the volumes reports I receive from my ISP and on the Project:Turris website.

For example, I received the following measurement data for March from these 3 sources:

  • ISP: 482 GB
  • Project Turris: 476 GB
  • Majordomo: 382 GB

To my mind, Majordomo should be the most accurate, since it’s tracking literally every byte travelling through the router, but perhaps there are know issues with it? Anyone have any insight?

Maybe majordomo is counting only PHY. not overhead of your traffic.

What does PHY mean? I’m not familiar with the term.

I suppose