centos安裝：
yum install ceph-common
ubuntu安裝：
apt-get install ceph-common

安裝後，能在python模組中匯入rbd與rados模組 似乎不使用與在windows或者Macos上

shell 命令檢視:
rbd diff pool_name/image_name | awk ‘{ SUM += $2 } END { print SUM/1024/1024 ” MB” }’

rbd diff pool_name/image_name | awk '{ SUM += $2 } END { print SUM/1024/1024 " MB"
 
 }'

# coding=utf-8

import rados
import rbd

cluster = rados.Rados(conffile='/etc/ceph/ceph.conf')
print cluster
cluster.connect()


def getUsedSize(pool_name, image_name):
    # 內部變數呼叫外部變數，必須使用一個class
    class ImageStorage: pass

    storage = ImageStorage()
    storage.used = 0

    def iterate_cb(offset, length, exists)
 
:
        print 'iterate_cb'
        print 'offset: ', offset, ' length: ', length, ' exists: ', exists
        storage.used += length

    with cluster.open_ioctx(pool_name) as ioctx:
        print 'pool state', ioctx.get_stats()
        rbd_inst = rbd.RBD()
        with rbd.Image(ioctx, image_name) as
 
 image:
            print 'image size: ', image.size()
            print 'image stat: ', image.stat()
            print 'iamge stripe_unit: ', image.stripe_unit()
            print 'image stripe_count: ', image.stripe_count()
            print image.diff_iterate(0, 10485760, None, iterate_cb)

    return storage.used


size = getUsedSize('rbd', 'test')
print size,'byte     ', size/1024**2,'MB'