> I could have one document per metric, leading to a small number of documents, but with each document containing ticks for every 5-second interval of any given day, these documents would quickly become huge.
This would not only make the docs large, but you'd have a trail of huge outdated docs. You would get n-squared storage problems quickly. Remember that all versions of a doc are stored until you do a compaction. I'd suggest one doc per second containing all the metric values for that second.
