Cloud computing is based on cloud storage. Cloud storage through a variety of technical storage device abstraction into virtual storage resource pool. Compared with the traditional way of storage, it has the scalability and high performance, low cost and other advantages. Different cloud storage systems have different technical architecture and characteristics. From the perspective of metadata if there is a center node, with and without the typical cloud storage system to do a simple introduction and mainly for open source without Gluster center system are analyzed in focus.