OpenIndiana is an open-source operating system that is part of the illumos project, designed to be a continuation of the OpenSolaris OS. It aims to maintain the legacy of Solaris by providing a robust platform for servers and desktops, combining advanced enterprise features with a community-driven development model. OpenIndiana is known for its use of the ZFS filesystem, network virtualization, and DTrace for real-time debugging and performance analysis. Users can expect a UNIX-like environment with a focus on stability, scalability, and data management.