A metric supports data retention (TTL); the swagger docs say this is number of days.
There is also a default TTL which is in days but converted internally into seconds:
Looking at when metrics are created, i can't see any conversion from days to seconds for metrics; so any data i create with a Metric DataRetention of 30 "days" gets removed straight away.

So my question is:
or
Or...have i missed something... ?

Cheers.