Use the CALIBRATE_IO Utility

Oracle provides a built in package dbms_resource_manager.calibrate_io which, like the ORION tool, generates workload on the I/O subsystem. However, unlike ORION, it works with your running Oracle database, and it generates statistics for the optimizer. Therefore, you should run calibrate_io and gather statistics for your application schema at least once before launching your application.

The calibrate_io script as provided in the Oracle documentation and presented here using our recommended values for <DISKS> and <MAX_LATENCY>.

SET SERVEROUTPUT ON
DECLARE
 lat INTEGER;
 iops INTEGER;
 mbps INTEGER;
BEGIN
-- DBMS_RESOURCE_MANAGER.CALIBRATE_IO (<DISKS>, <MAX_LATENCY>, iops, mbps, lat);
 DBMS_RESOURCE_MANAGER.CALIBRATE_IO (1000, 10, iops, mbps, lat);
 DBMS_OUTPUT.PUT_LINE ('max_iops = ' || iops);
 DBMS_OUTPUT.PUT_LINE ('latency = ' || lat);
 dbms_output.put_line('max_mbps = ' || mbps);
end;
/

Typically you will see output similar to the following:

max_iops = 134079
latency  = 0 
max_mbps = 1516

Advise that timed_statistics must be set to TRUE before calibrate_io is run.

This can be checked with:

SQL> show parameter timed_statistics
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
timed_statistics boolean TRUE