Abstract: A cloud data storage system is provided for multiple clients to access data of files comprising at least one node connecting to a first storage means; at least one namenode module for processing file operations issued from the clients, namenode module issuing data access instructions to access and maintain the metadata on the first storage means; at least one datanode module respectively executing on at least one node, each datanode module functioning to scan and access a second storage means connected thereto; at least one data import module selectively executing on nodes in which datanode module are executing, the data import module scanning a second storage means newly connected to the cloud data storage system and obtaining a corresponding metadata, and executing data migration operation for the data in second storage means without actual physical uploading operation.

Abstract: A cloud data storage system is provided for multiple clients to access data of files comprising at least one node connecting to a first storage means; at least one namenode module for processing file operations issued from the clients, namenode module issuing data access instructions to access and maintain the metadata on the first storage means; at least one datanode module respectively executing on at least one node, each datanode module functioning to scan and access a second storage means connected thereto; at least one data import module selectively executing on nodes in which datanode module are executing, the data import module scanning a second storage means newly connected to the cloud data storage system and obtaining a corresponding metadata, and executing data migration operation for the data in second storage means without actual physical uploading operation.

Abstract: The invention discloses a network-attached storage system including an interface module, a plurality of storage devices and a storage module. The interface module is configured to be attached to a network. The interface module is for receiving a transmission protocol information transmitted over the network, and processing the information into storage data and access instructions. The storage module is for receiving the storage data and the access instructions, and controlling, according to the access instructions, access of the storage data to the primary storage devices through a transmission interface.