dbms_resource_manager.calibrate_io, strange numbers

  • From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
  • To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 5 Oct 2011 15:25:50 +0200

Hi,

To enable auto dop on a new system, I ran the calibrate_io procedure from the 
dbms_resource_manager package.
However the results are a bit strange.
The actual latency is reported as 0 and so is the max_mbps.
The max_pmbps however is set to 186.

Monitoring with collectl showed network troughput of arround 230 MB/s

Db version is 11.2.0.2 (64bit) on OL 5.4 (64bit).
Storage is NetApp, accessed via dNFS (using 2 1 Gbit/s connections)

I searched MOS and google, but no real bugs popped up.
What can explain the actual latency and the max_mbps to be set to 0?


SQL> @io_callibration.sql
SQL> set serveroutput on
SQL> set timing on
SQL> set echo on
SQL>
SQL> DECLARE
  2
  3    l_actual_latency    integer;
  4    l_max_iops          integer;
  5    l_max_mbps          integer;
  6
  7  BEGIN
  8
  9    dbms_resource_manager.calibrate_io
 10      ( num_physical_disks  =>  30,
 11        max_latency         =>  20,
 12        max_iops            =>  l_max_iops,
 13        max_mbps            =>  l_max_mbps,
 14        actual_latency      =>  l_actual_latency
 15      );
 16
 17    dbms_output.put_line ('max_iops = ' || l_max_iops);
 18    dbms_output.put_line ('actual_latency  = ' || l_actual_latency);
 19    dbms_output.put_line('max_mbps = ' || l_max_mbps);
 20
 21  END;
 22  /

max_iops = 11750
actual_latency  = 0
max_mbps = 0

PL/SQL procedure successfully completed.

Elapsed: 00:53:20.45
SQL>
SQL>
SQL> select * from gv$io_calibration_status;

   INST_ID STATUS        CALIBRATION_TIME
---------- ------------- 
---------------------------------------------------------------------------
         1 READY         05-OCT-11 02.56.40.929 PM

Elapsed: 00:00:00.00
SQL>
SQL> set linesize 150
SQL> column start_time format a30
SQL> column end_time format a30
SQL> column num_physical_disks format 9999 heading NPD
SQL> select * from dba_rsrc_io_calibrate;

START_TIME                     END_TIME                         MAX_IOPS   
MAX_MBPS  MAX_PMBPS    LATENCY   NPD
------------------------------ ------------------------------ ---------- 
---------- ---------- ---------- -----
05-OCT-11 02.03.20.489842 PM   05-OCT-11 02.56.40.928773 PM        11750        
  0        186          0    30

Elapsed: 00:00:00.00


Kind regards,

Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer

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