Not all measurements would have the same sampling rate, but they do need to be analysed together.
For example, board temp#3860erature could be sampled every 10 seconds, but S.M.A.R.T.attributes for hard-disks may only be read once every hour. Is it better to store both of these values together or should they be stored separately?
Keeping them together would have some values staying the same value for thousands of entries - which should compress well, but nonetheless would have a storage overhead. Keeping them separately would need to join two different series with dissimilar intervals outside the db - it might perform much worse than if the data were in one series - though, there would be less data to be read. Some kind of reconciliation would also have to be run to pinpoint the value of a low frequency measurement at the same time as a high frequency one.
This is referencing #3860