Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







dbms_resource_manager.calibrate_io tips

Oracle Database Tips by Donald BurlesonDecember 31, 2015

Question:  I noticed the dbms_resource_manager.calibrate_io procedure and I was wondering how dbms_resource_manager.calibrate_io can be used to monitor Oracle disk I/O.  Also, what does the calibrate I/O procedure do?

Answer:  The dbms_resource_manager.calibrate_io stored procedure is used to generate a randomized read-only workload for volumetric testing purposes.

The calibration of the I/O is used to determine the amount of megabytes per second of data volume that can used on the database without performance degradation.   There are a few restrictions associated with the procedure.

- The TIMED_STATISTICS parameter must be set to TRUE, which is the default when STATISTICS_LEVEL=TYPICAL.
- Data files must be accessed using asynchronous I/O. This is the default when ASM is used.
- The procedure must be called by a user with the SYSDBA privilege.

You can check your current asynchronous I/O setting for your data files using this dictionary SQL.

   v$datafile d,
   v$iostat_file i
   d.file# = i.file_no
   i.filetype_name  = 'Data File';

WARNING:  Obviously, dbms_resource_manager.calibrate_io is not to be used in a production environment.  Rather, it is to be used in a test database to generate specific workload volumes.

Here is a sample invocation of dbms_resource_manager.calibrate_io:

  lat  INTEGER;
  iops INTEGER;
  mbps INTEGER;
      1 /* # of disks */
      , 10 /* maximum tolerable latency in milliseconds */
      , iops /* I/O rate per second */
      , mbps /* throughput, MB per second */
      , lat  /* actual latency in milliseconds */
  DBMS_OUTPUT.PUT_LINE('max_iops = ' || iops);
  DBMS_OUTPUT.PUT_LINE('latency  = ' || lat);
  DBMS_OUTPUT.PUT_LINE('max_mbps = ' || mbps);
The procedure calibrate_io of the package dbms_resource_manager accepts two INOUT parameters:
   - num_physical_disks - This is the number of physical disks spindles.

   - max_latency - This is the maximum latency for the disk access (in milliseconds)

And it has three OUT parameters.  After running this procedure you can view the results using the v$io_calibration_status and for RAC, the gv$io_calibration_status views.

   - max_iops - This is the max number of I/O operations/ per second.

   - max_mbps - This is the maximum Megabytes per second.

   - actual_latency - This is the actual latency observed during the test.

The results from this output will be displayed in these views:

- v$io_calibration_status:  This will show you the progress of the I/O calibration task:
select * from v$io_calibration_status

dba_rsrc_io_calibrate view:  This will show all three of the output parameters. Plus the two input parameters, and a start_time and end_time for multiple calibration runs:

Oracle Training from Don Burleson 

The best on site "Oracle training classes" are just a phone call away! You can get personalized Oracle training by Donald Burleson, right at your shop!

Oracle training



Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2017

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.

Remote Emergency Support provided by Conversational



Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster