Tell all SAN communication becomes even more important than the number of processors, because the SAN relays so much information. Under distributed parallel clustering, storage is split off from the server CPUs. Each server has redundant arrays of independent disks or other high-bandwidth storage subsystems. The SAN must handle not only requests from the clients and other normal server functions but also the data storage. As clustering products gradually emerge, load balancing will become the industry's war cry.
Load balancing means directing routines to individual processors.
The cluster OS makes the decisions on where to send tasks to equalize the workload among different servers and processors. A distributed parallel cluster of eight servers with four processors apiece has 24 possible routes to compute something. The processors don't work in concert as in a massively parallel system. Instead, each works separately on a manageable task. An alternative to this scenario is Oracle Corp.'s Parallel Server for NT, which does distributed cooperative clustering on up to four nodes.