As organizations accelerate the deployment of mission-critical applications on UNIX(R), Microsoft(R) Windows NT(R) and Windows 2000 platforms, they sometimes face unacceptable levels of business disruption due to downtime. To alleviate this problem, organizations are looking for new ways to achieve the level of availability previously enjoyed in IBM(R) S/390(R) data centers. The GeoSAN(TM) Clustering Services solution from Hitachi Data Systems leverages best-of-breed storage, storage area network (SAN) fabric components and optical networks to provide disaster recovery and business continuity over metropolitan area networks (MANs) spanning up to 100 km. This white paper explains how the GeoSAN Clustering Services solution helps leading-edge organizations face the critical requirements of disaster tolerance and maximum data protection. (2001)