Functioning computer systems are rarely useless; the E8000 systems the OP has will run software just like they did a few years ago when they were purchased. The most important question is: what do you want this cluster to do? If you want the experience of building it, including solving the HW issues of racking and stacking, and the software issues of cluster management software, job scheduling and resource management, then don't throw the equipment away. There are many opportunities for making decisions that require problem-solving and resourcefulness. Plenty of FOSS solutions, even while using only the built-in network connections for an interconnect. If you have some HPC or scientific cluster-aware software in mind that you want to run, tailor your software configuration to run that. The folks who built Beowulf clusters in the early 2000s had a goal in mind; often, that goal was to provide an environment to develop their own MPI software to simulate some phenomena they were interested in. Are you a programmer, or want to learn parallel programming? Are you offering your cluster to folks who are learning parallel programming? http://www.open-mpi.org/ has good information, and FOSS implementations for Linux distributions. There are also Windows clustering solutions, if that's what your user base requires; not free, obviously. So, what do you want this cluster to do?