The prime goal of this article is to discuss about Online Hard Drive. Online hard disk drives, also known as foriegn storage, is a popular choice to backup your files. With all the advances in storage technology and Internet technology, the demand for document synchronization between personal multiple devices continues to grow. In the meantime, the particular development of distributed calculating, parallel computing, and grid calculating has boosted and prolong the service for online cloud storage, making it into Software Being a Service (SAAS). Here explain on Ease of management, Low cost and Flexibility.