DBMS_Resource_Manager has a procedure called Calibrate_IO with a Physical Disks input parameter. The documentation says this value should be set to the...
Approximate number of physical disks in the database storage
With a logical drive striped across an unknown number of disks in a SAN disk group containing 30 drives, I'm not sure what this means. I ran the procedure for values of 1 and 30, yet the IOPS, MBPS and latency were nearly identical.
Is this number just for informational purposes or is it actually used? If the the later, then what should it be set to when there is not a one to one relationship between logical disks and physical disks?
Block to run procedure:
set serveroutput on; DECLARE vDisks Binary_Integer := 30; vMaxLatency Binary_Integer := null; vMaxIOPS Binary_Integer; vMaxMBPS Binary_Integer; vActualLatency Binary_Integer; BEGIN DBMS_RESOURCE_MANAGER.Calibrate_IO(Num_Physical_Disks => vDisks , Max_IOPS => vMaxIOPs, Max_MBPS => vMaxMBPS , Actual_Latency => vActualLatency); DBMS_OUTPUT.PUT_LINE(' Max IOPS:' || vMaxIOPS); DBMS_OUTPUT.PUT_LINE(' Max MBPS:' || vMaxMBPS); DBMS_OUTPUT.PUT_LINE('Actual Latency:' || vActualLatency); END; / select * from dba_rsrc_io_calibrate;