Hi,
i'm doing some IO performance test on my new server.
I'm using IO Calibration and the database version was 11.2.0.4.1 and i've a question about the differents of value NONE and SETALL of
filesystemio_options.
I use filesystem with RAID 10.
Test 1
disk_asynch_io=true
filesystemio_options=none
Execute io calibration:
set serveroutput on
declare
l_latency integer;
l_iops integer;
l_mbps integer;
begin
dbms_resource_manager.calibrate_io (
6, /* # of disks */
10, /* max latency */
l_iops, /* I/O Ops/sec */
l_mbps, /* MBytes/sec */
l_latency /* actual latency */
);
dbms_output.put_line ('I/O Ops/sec = '|| l_iops);
dbms_output.put_line ('Actual Latency = '|| l_latency);
dbms_output.put_line('MB/sec = '|| l_mbps);
end;
/
I/O Ops/sec = 4194021
Actual Latency = 0
MB/sec = 32424
Top 5 Timed Events Avg %Total
~~~~~~~~~~~~~~~~~~ wait Call
Event Waits Time (s) (ms) Time
----------------------------------------- ------------ ----------- ------ ------
Disk file I/O Calibration 307,058,131 6,903 0 99.8
CPU time 10 .1
os thread startup 28 1 47 .0
resmgr:cpu quantum 38 1 34 .0
enq: PR - contention 3 0 45 .0
-------------------------------------------------------------
Test 2
disk_asynch_io=true
filesystemio_options=setall
Execute io calibration:
set serveroutput on
declare
l_latency integer;
l_iops integer;
l_mbps integer;
begin
dbms_resource_manager.calibrate_io (
6, /* # of disks */
10, /* max latency */
l_iops, /* I/O Ops/sec */
l_mbps, /* MBytes/sec */
l_latency /* actual latency */
);
dbms_output.put_line ('I/O Ops/sec = '|| l_iops);
dbms_output.put_line ('Actual Latency = '|| l_latency);
dbms_output.put_line('MB/sec = '|| l_mbps);
end;
/
I/O Ops/sec = 5124
Actual Latency = 11
MB/sec = 558
Top 5 Timed Events Avg %Total
~~~~~~~~~~~~~~~~~~ wait Call
Event Waits Time (s) (ms) Time
----------------------------------------- ------------ ----------- ------ ------
Disk file I/O Calibration 545,766 3,601 7 99.8
CPU time 2 .1
db file sequential read 401 2 4 .0
os thread startup 20 1 46 .0
db file scattered read 79 0 4 .0
Why setting filesystemio_option=setall i've this performance problem?
All datafile are in ASYNCH_IO.
Asynch IO is active at SO level:
[oracle@] $ cat /proc/sys/fs/aio-max-nr
1048576
[oracle@]$ cat /proc/sys/fs/aio-nr
12544
Thank you.