I think, like most people, I will disagree with this:<p>&gt; <i>In my opinion, my thesis from GopherCon 2014 still holds: services should only log actionable information.</i><p>This assumes that I have future knowledge of which logged events will be actionable.<p>I used to work in the classifieds department of a newspaper. The rule of thumb was that the cover of the newspaper was worthless by 11am, the classifieds by 2pm.<p>But that&#x27;s not quite true. Every single edition of a newspaper retains a small probability of turning out to be very important at some unknown future time. Hence the practice of archiving.<p>So it is with logs. In my day job I have on several occasions turned to raw logs in order to reconstruct the history of unexpected events.<p>What metric, to take an actual example, tells me that a user was trying to evade export control by hopping to a VPN halfway through a session? Which gauge tells me that an error was caused by the interaction of third party javascript and an obscure web browser?<p>For myself, I draw the boundary differently. Logging is for events with identity, events that will be inspected individually. Metrics are for events that will never have identity and will only be understood statistically.