1.让OpenStack删除卷更快
为什么速度这么慢？
当我们执行删除卷命令以后，openstack会尝试去清除卷上的数据，他是如何清除的呢？
其实他是通过dd命令填充空白数据上去（dd if=/dev/zero）。这样子的清理方式目的是
为了彻底的清除数据，保证数据安全。但是对于ceph作为后端存储的情况而言，我们把image删
除了，数据也就相当安全了。这样子的操作并没有太多用处。特别是存储空间大于50GB的情况下，会操作很久。
我们可以做那些什么？
直接修改/etc/cinder/cinder.conf 配置文件：
# Method used to wipe old volumes (string value) # Allowed values: none, zero, shred volume_clear = none openstack-config --set /etc/cinder/cinder.conf DEFAULT volume_clear none
默认值是zero，我们配置成none，就跳过清理这步。如果我们想只清理前100MB呢？
# Method used to wipe old volumes (string value) # Allowed values: none, zero, shred volume_clear = zero # Size in MiB to wipe at start of old volumes. 0 => all (integer value) volume_clear_size = 100 cinder 中clear_volume段代码 def clear_volume(volume_size, volume_path, volume_clear=None, volume_clear_size=None, volume_clear_ionice=None, throttle=None): """Unprovision old volumes to prevent data leaking between users.""" if volume_clear is None: volume_clear = CONF.volume_clear if volume_clear_size is None: volume_clear_size = CONF.volume_clear_size if volume_clear_size == 0: volume_clear_size = volume_size if volume_clear_ionice is None: volume_clear_ionice = CONF.volume_clear_ionice LOG.info(_LI("Performing secure delete on volume: %s"), volume_path) # We pass sparse=False explicitly here so that zero blocks are not # skipped in order to clear the volume. if volume_clear == ‘zero‘: return copy_volume(‘/dev/zero‘, volume_path, volume_clear_size, CONF.volume_dd_blocksize, sync=True, execute=utils.execute, ionice=volume_clear_ionice, throttle=throttle, sparse=False) else: raise exception.InvalidConfigurationValue( option=‘volume_clear‘, value=volume_clear)
原文：http://www.cnblogs.com/wangyifu/p/7660309.html