Computing clusters

• The Norma computing cluster (see images below). Norma is a stateless Beowulf cluster based on the Caos NSA GNU/Linux distribution. It comprises 36 cores and 40 Gbytes of physical memory distributed over 9 nodes connected via a dedicated Gigabit ethernet switch. Each of the eight diskless (compute-only) nodes offers four cores, four Gbytes of physical memory and two (gigabit) network interfaces. The head node comes with four cores, eight Gbytes of physical memory, 1.5 Tbytes of storage in the form of a RAID-5 array of four disks, three (gigabit) network interfaces, and a nvidia CUDA-enabled GPU.





• The good-old Nefeli computing cluster (see image below). This cluster is heterogeneous and comprises 18 nodes connected via a 100Mbps full-duplex fast ethernet switch. Individual nodes range from one Pentium IV machine with 512 MBytes of main memory, to nine Pentium III machines (at 733 MHz) with 320 MBytes of main memory. All nodes are complete with disks, video cards, monitors, keyboards, etc. Nefeli should more properly be described as a 'CoW' (Cluster of Workstations), although several pedants still call it an 'undergraduate terminal room'. Although Nefeli does function as an undergraduate terminal room, there are significant differences software-wise: Nefeli is in reality an OpenMosix-based Single System Image (SSI) cluster. The OpenMosix linux kernel allows for cluster-wide load balancing via transparent process migration between the cluster's nodes. It also offers a cluster-wide filesystem in the form of oMFS and DFSA. In addition to OpenMosix, the cluster supports MPI program execution via two different MPI implementations and provides a batch queueing system in the form of the Sun Grid Engine (SGE).