Population aging in the world causes medical expenses to soar. Preventive health care attracts people and government's close attention. Integrated electronic health records (EHRs) and Personal Health Records (PHRs) play a crucial role in providing continuous health care. Although, IHE (Integrating the Healthcare Enterprise) has developed the XDS (Cross Enterprise Document Sharing) integration profile for sharing clinical documents among computer systems in healthcare, the XDS integration profile may not directly support cloud computing environments where repository systems are heterogeneous and virtualized. In this paper, we propose a PHR cloud system architecture based on the cloud computing Service Model defined by the National Institute of Standards and Technology (NIST), and adopt the IHE XDS integration profile for system interoperability. To enhance computation power and system scalability we include Hadoop parallel computing model and implement a NoSQL storage layer in this PHR cloud architecture. Our approach presented here to PHR Systems Cloud architecture could be a paradigm for sharing documents in health care settings and supporting cloud computing as well.