VCS (Veritas Cluster Server)
Veritas Cluster Server (VCS) is a high-availability cluster software for Unix, Linux and Microsoft Windows computer systems, created by Veritas Software. It provides application cluster capabilities to systems running other applications, including databases, network file sharing, and electronic commerce websites. The high-availability clusters (HAC) improves application availability by failing or switching them over in a group of systems—as opposed to high-performance clusters, which improve application performance by running them on multiple systems simultaneously.