Macro-Clusters, a Way to Adapt New Technologies in Existing Large Computing Clusters

A series of new interconnect technologies are emerging on the market, HyperTransport PCI-Express, Infiniband and 10 Gigabit Ethernet. Some are very interesting as cluster interconnects and others not at all. A description is made of methods to use this cluster oriented interconnects in different ways. In order to adapt easily to existing clusters the term of Macro-Clusters is introduced to define small sub-clusters with a defined function that can be used independently or coupled to large cluster networks. Some notice is given on how to interconnect hardware and software of the different technologies and some remarks about cost performance relations are included. In the Appendix test results are mentioned for bandwidth and connections to the CERN storage system.