一直以来，都是用DD或者ORION来测试I/O 的mps或iops，但是，DD不准，Orion用起来有比较麻烦。好在，Oracle也意识到了这个问题，在Oracle 11g中提供了一个程序包，来对IO系统进行简单的测试，这个程序包就是：

DBMS_RESOURCE_MANAGER.CALIBRATE_IO

先来看看使用条件：

1。用户必须具有SYSDBA权限

2。timed_statistics必须设置为TRUE

3。必须打开异步IO,当使用文件系统时，可以设置FILESYSTEMIO_OPTIONS=SETALL，可以通过如下SQL查询是否启用了异步IO

COL NAME FORMAT A50

SELECT NAME,ASYNCH_IO FROM V$DATAFILE F,V$IOSTAT_FILE I WHERE F.FILE#=I.FILE_NO AND FILETYPE_NAME='Data File';

4。一个实例只运行一个CALIBRATE_IO程序

方法：

SET SERVEROUTPUT ON
DECLARE
  lat  INTEGER;
  iops INTEGER;
  mbps INTEGER;
BEGIN
-- DBMS_RESOURCE_MANAGER.CALIBRATE_IO (, , iops, mbps, lat);
   DBMS_RESOURCE_MANAGER.CALIBRATE_IO (2, 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;
/

还有，几个注意事项：

• Only run one calibration at a time on databases that use the same storage subsystem. If you simultaneously run the calibration across separate databases that use the same storage subsystem, the calibration will fail.

• Quiesce the database to minimize I/O on the instance.

• For Oracle Real Application Clusters (Oracle RAC) configurations, ensure that all instances are opened to calibrate the storage subsystem across nodes.

• For an Oracle Real Application Clusters (Oracle RAC) database, the workload is simultaneously generated from all instances.

• The num_physical_disks input parameter is optional. By setting the num_physical_disks parameter to the approximate number of physical disks in the database's storage system, the calibration can be faster and more accurate.

• In some cases, asynchronous I/O is permitted for data files, but the I/O subsystem for submitting asynchronous I/O may be maximized, and I/O calibration cannot continue. In such cases, refer to the port-specific documentation for information about checking the maximum limit for asynchronous I/O on the system.

下面，看看具体的使用例子：

SQL*Plus: Release 11.2.0.1.0 Production on 星期一 10月 25 09:56:05 2010

Copyright (c) 1982, 2010, Oracle. All rights reserved.

SUNDOG315>conn / as sysdba
已连接。
SUNDOG315>show parameter timed

NAME TYPE
------------------------------------ --------------------------------
VALUE
------------------------------
timed_os_statistics integer
0
timed_statistics boolean
TRUE
SUNDOG315>col name format a50
SUNDOG315>select name,asynch_io from v$datafile f,v$iostat_file i
2 where f.file#=i.file_no
3 and filetype_name='Data File';

NAME ASYNCH_IO
-------------------------------------------------- ---------
C:ORACLEAPPADMINISTRATORORADATATESTSYSTEM01. ASYNC_ON
DBF

C:ORACLEAPPADMINISTRATORORADATATESTSYSAUX01. ASYNC_ON
DBF

C:ORACLEAPPADMINISTRATORORADATATESTUNDOTBS01 ASYNC_ON
.DBF

C:ORACLEAPPADMINISTRATORORADATATESTUSERS01.D ASYNC_ON
BF

NAME ASYNCH_IO
-------------------------------------------------- ---------


SUNDOG315>set serveroutput on
SUNDOG315>DECLARE
2 lat INTEGER;
3 iops INTEGER;
4 mbps INTEGER;
5 BEGIN
6 -- DBMS_RESOURCE_MANAGER.CALIBRATE_IO (, , iops, mbps, lat);
7 DBMS_RESOURCE_MANAGER.CALIBRATE_IO (2, 10, iops, mbps, lat);
8
9 DBMS_OUTPUT.PUT_LINE ('max_iops = ' || iops);
10 DBMS_OUTPUT.PUT_LINE ('latency = ' || lat);
11 dbms_output.put_line('max_mbps = ' || mbps);
12 end;
13 /
max_iops = 77
latency = 12
max_mbps = 43

PL/SQL 过程已成功完成。

SUNDOG315>

具体请参见官方文档：http://download.oracle.com/docs/cd/E11882_01/server.112/e16638/iodesign.htm#CHDFBGFB