(Fermi National Accelerator Lab. (US))
The Tier-0 processing system is the initial stage of the multi-tiered computing system of CMS. It is responsible for the first processing steps of data from the CMS Experiment at CERN. This talk covers the complete overhaul (rewrite) of the system for the 2012 run, to bring it into line with the new CMS Workload Management system, improving scalability and maintainability for the next few years.
In the last CHEP we presented the current CMS Tier0 system. It has worked very well for us, but due to the deployment of a new CMS workload management system this year, we were looking at changes to bring the Tier0 in sync with it. The changes were extensive enough to warrant a complete overhaul, a redesign based on lessons learned and rewrite from scratch.