The R/s dataflow depicts the rate at which synchronous and asynchronous reads are occurring in the database or partition you are monitoring.
At each refresh, Spotlight captures the number of reads—both synchronous and asynchronous—per second occurring in the database or partition that you are monitoring.
The line graph that overlays the dataflow plots the total read rate captured over the series of refreshes that have occurred during the Spotlight session.
Click the R/s dataflow to open the Databases drilldown. This drilldown provides details about database or partition that you are monitoring. The I/O tab on the drilldown is in immediate focus to help you pinpoint I/O flow problems in the database or partition.