Deployment and Operations of the CMS Prompt Skimming System

This article will present a system deployed at Tier-1 computing centers used to provide skimmed datasets for commissioning and analysis activities, and operational experience gained from the first period of data taking. CMS has many automated and time critical workflows that are used to monitor and commission the detector. Most of the automated workflows are run at the Tier-0 computing facility at CERN, but CMS has recently deployed an infrastructure for automated workflow submission at the Tier-1 centers. The Tier-1 skimming system automatically tracks and submits workflows from CERN to the Tier-1 centers as the data arrives through the grid interfaces. The Tier-1 facilities do not have the same low latency access to the data, but there is a larger pool of processing and storage resources at the remote sites than at CERN. The prompt skimming system is an interesting example of utilizing the Tier-1 centers as a natural extension of the data acquisition system to the remote facilities.