Apparatus and method for storing data

The present application provides a storage apparatus for storing data. The storage apparatus comprises storage means for storing data, committing means for committing the availability of a certain storage space to a source device, detecting means for detecting the availability of the certain storage space to produce a detection result, and communication means for informing the source device the detection result, whereby the source device takes corresponding action(s) according to the detection result. In this way, each storage device of a group is bound by its commitment, if it violates its commitment, it risks the loss of its file(s) stored on other members' storage space.