The default RRA stores primary data points for a year. No more RRA can be added. The created RRD is for an acquisition period much less than a year, typically about some days, a few weeks or months.

This constructor neads an argument named step which is the period of acquisition. The natural step units are day(d), week(w) and month(m), although second(s), minute(m), hour(h) and quarter(q) are allowed.

    $creator = RRDTool::Creator::YearPDP(-step => "1w") ;