Storage on-demand system, and method for processing data in the same

Data in a storage area to be returned from among storage areas of a storage system is deleted without fail, thereby ensuring data security.When a user's storage-on-demand management program is activated in response to a return request from user A's console terminal , the return request is transferred via a communication network to a server , and a provider's storage on-demand management program makes a request to a storage management program for volume initialization and data deletion. After the storage management program issues a volume initialization command after receiving the above request, a control program is activated to initialize the designated volume. Subsequently, the user A's volume access right is deleted by the processing executed by the provider's storage-on-demand management program , and it is reported to the console terminal that the volume initialization and the volume separation have been conducted.