GroupKit is a Tcl/Tk library that makes it easy to prototype and build real-time collaborative applications (groupware), such as multi-user drawing tools, text editors, meeting tools, and much more.
Linux Cluster Manager is designed as a beowulf cluster setup and management tool. LCM can run bulk commands, give real time performance and status monitoring, search running processes, and provide system imaging at a file or block level over the network
PRATIMA, an Asynchronous Remote Volume Replicator for Linux:
Pratima performs online, real-time, reliable and efficient block level data replication to a remote computer over a network in both synchronous and asynchronous modes for Linux.