When a storage pool has only one mount point (that is, just one drive) available to it through the device class, data cannot be reclaimed from one volume to another within that same storage pool.

• 当一个存储池只有一个挂接点（也就是只有一个驱动器）可用到这个设备类，在同一个存储池里的数据不能被回收从一个卷到另一个卷。