Cycle Computing announced a cluster 3 times the size of Tanuki, or 30,000 cores, which cost $1279/hour to operate for a Top 5 Pharma. It performed genuine scientific work — in this case molecular modeling — and a ton of it. The complexity of this environment did not necessarily scale linearly with the cores.
Setting up a 10,000-core physical server cluster to run supercomputing workloads is a tough task that can take weeks or months, and cost millions of dollars including the servers, storage, switching, and personnel overhead. And the thing about a cluster is that no matter how hard you try to share it, it is very tough to get anywhere near peak utilization over the course of the year.