+B<MIN>, B<MAX>, B<LAST>.
+
+=over
+
+=item AVERAGE
+
+the average of the data points is stored.
+
+=item MIN
+
+the smallest of the data points is stored.
+
+=item MAX
+
+the largest of the data points is stored.
+
+=item LAST
+
+the last data points is used.
+
+=back
+
+Note that data aggregation inevitably leads to loss of precision and
+information. The trick is to pick the aggregate function such that the
+I<interesting> properties of your data is kept across the aggregation
+process.
+
+
+The format of B<RRA> line for these