http://ceph.com/planet/openstack-ceph-rbd-and-qos/
https://inter6.github.io/2016/04/20/cinder-volume-qos/
http://docs.aws.amazon.com/ko_kr/AWSEC2/latest/UserGuide/benchmark_procedures.html

# source /root/admin_openrc

:: consumer
front-end : QOS policy will be applied to Compute. (Hypervisor 에서 제어)
back-end : QOS policy will be applied to the Block Storage back end. (스토리지에서 제어)
both : QOS policy will be applied to both Block Storage and Compute.

# cinder qos-create Low-speed consumer="front-end" total_iops_sec=1000 total_bytes_sec=83886080
+----------+-----------------------------------------------------------+
| Property |                           Value                           |
+----------+-----------------------------------------------------------+
| consumer |                         front-end                         |
|    id    |            4fd882ec-d879-4bd6-bba3-5f3a5645ded9           |
|   name   |                         Low-speed                         |
|  specs   | {'total_iops_sec': '1000', 'total_bytes_sec': '83886080'} |
+----------+-----------------------------------------------------------+

# cinder qos-list
+--------------------------------------+-----------+-----------+-----------------------------------------------------------+
|                  ID                  |    Name   |  Consumer |                           specs                           |
+--------------------------------------+-----------+-----------+-----------------------------------------------------------+
| 4fd882ec-d879-4bd6-bba3-5f3a5645ded9 | Low-speed | front-end | {'total_iops_sec': '1000', 'total_bytes_sec': '83886080'} |
+--------------------------------------+-----------+-----------+-----------------------------------------------------------+

# cinder type-create Low-speed
+--------------------------------------+-----------+-------------+-----------+
|                  ID                  |    Name   | Description | Is_Public |
+--------------------------------------+-----------+-------------+-----------+
| f759c906-3db4-43b3-84d9-3e0b6dfb335b | Low-speed |      -      |    True   |
+--------------------------------------+-----------+-------------+-----------+

usage: cinder qos-associate <qos_specs> <volume_type_id>
# cinder qos-associate 4fd882ec-d879-4bd6-bba3-5f3a5645ded9 f759c906-3db4-43b3-84d9-3e0b6dfb335b

# cinder create --display-name low_speed --volume-type Low-speed 10


비교>
/HDD1  Qos 설정을 하지 않은 디스크
/HDD2  Low-speed type 설정 디스크

read : io=6144.0MB, bw=285197KB/s, iops=71299 , runt= 22060msec
Disk stats (read/write):
  vdb: ios=267781/8, merge=1298212/10, ticks=2453760/227, in_queue=2454982, util=99.70%
write: io=6144.0MB, bw=211066KB/s, iops=52766 , runt= 29808msec
Disk stats (read/write):
  vdb: ios=0/212499, merge=0/1347972, ticks=0/3280782, in_queue=3281403, util=99.81%


read : io=4769.9MB, bw=81239KB/s, iops=20309 , runt= 60123msec
Disk stats (read/write):
  vdd: ios=105284/9, merge=1115019/8, ticks=6575744/21676, in_queue=6608682, util=100.00%
write: io=4730.2MB, bw=80664KB/s, iops=20166 , runt= 60047msec
Disk stats (read/write):
  vdd: ios=0/108938, merge=0/1101349, ticks=0/6698051, in_queue=6699929, util=99.99%