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Maintaining Large Linux Clusters
pompousjerk writes "A paper landed on arXiv.org on Friday titled Installing, Running and Maintaining Large Linux Clusters at CERN [PDF]. The paper discusses the management of the 1000+ Linux nodes, upgrading from Red Hat 6.1 to 7.3, securely installing over the network, and more. They're doing this in preparation for Large Hadron Collider-class computation."
"Why on earth would someone need a 1000+ node cluster?"
:-)
Look at google?
One application that benefits from adding the nodes (with almost linear scaling in performance) is the Monte Carlo radiation transport. For example, in medical physics people try to calculate a dose distribution in a human body for the various configuration of treatment accelerators. Monte Carlo simulation software "generates" random initial particles (with appropriate probabilities for given accelerator) and than tracks each particle as it propagates and interacts with surrounding tissue. Interactions are randomly generated (hence: Monte Carlo) but again randomness is biased according to the appropriate physics. Each such "history" can be independently generated by a different node thus making parallelization trivial.
In my lab I have assembled a 24-node cluster and it takes about 4-8 hr to calculate dose distributions for the most cases. With a 1000 node cluster it would be possible to do this sort of calculations routinely in clinics during the treatment planing and actual treatment. This will mean that the cancer patients will have improved survivability odds due to the more precise targeting of the tumors.
Cheers,
Beowulf's root
Perhaps the nodes are not all physically located in the same building, or are otherwise vulnerable to physical man-in-the-middle intrusions. If one adopts secure practices as a matter of principle, it saves having to go back and implement security as an afterthought someday when the situation changes in an unanticipated way.
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