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\section{Definition}
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The combined Computing, Software, and Analysis challenge of 2006 is an
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O(50) million event exercise to test the workflow and dataflow
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associated with the data handling model of CMS \cite{model, ctdr}. It is designed to be a
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25\% capacity test of what is needed for operations in 2008. The main
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components include:
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\begin{itemize}
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\item Preparation of large simulated datasets (some with High Level
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Trigger tags)
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\item Prompt reconstruction at Tier-0, including:
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\begin{itemize}
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\item Reconstruction at 40 Hz using the new CMSSW software framework
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\item Application of calibration constants from the offline database (DB)
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\item Generation of FEVT\footnote{``Full Event'' data, i.e. RAW+RECO
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which for this challenge was combined into one file stream},
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AOD\footnote{``Analysis Object Data'' (AOD) is a reduced collection of
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reconstruction products (i.e. DST)}, and Alignment/Calibration skim
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datasets known as ``AlCaReco'' skims
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\item Splitting of an HLT-tagged sample into O(10) streams
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\end{itemize}
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\item Distribution of all AOD and some FEVT to all participating
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Tier-1s (as well as to some Tier-2s)
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\item Calibration jobs on Alignment/Calibration datasets at Tier-1, Tier-2 and CAF
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\item Re-reconstruction performed at a Tier-1
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\item Skim jobs at some Tier-1s with data propagated to Tier-2s
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\item Physics jobs at Tier-2s and Tier-1s on AOD and Reco
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\end{itemize}
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While this is an exercise to test the data handling workflow under as
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realistic conditions as possible, it is not explicitly required that
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the software components are fully validated for physics performance at
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the time of the challenge. However, where possible we tried to
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maintain the maximum utility of the simulated, reconstructed, and
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selected samples for the analysis component of the exercise. The CMS
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computing model and is described in \cite{model} and \cite{ctdr}.
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%%\cite{}[Need references]
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\section {Success Metric}
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Success of the CSA06 challenge was pre-defined (June 2006) as meeting
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a series of
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binary metrics (succeed/fail) as well as a list of quantitative
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numbers based on the performances anticipated a half-year before the
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CSA06 challenge (and Service Challenge 4) began.
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The quantitative metrics
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are placed at two levels: a minimum
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threshold below which we consider a definite failure, and a goal which
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is considered achievable if everything runs well. No specific goals
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were placed on the number or results from the calibration, alignment,
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and analysis exercises other than to meet the overall daily job
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submission goal and to demonstrate the workflow associated with prompt
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calibration.
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The metrics were chosen to exercise a variety of important elements in
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the CMS computing model, though to enable the available effort to
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concentrate on particular functionality not all areas were tested.
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The metrics were chosen to ensure a broad participation of CMS
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computing facilities, to enable the experiment to demonstrate
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functionality critical to early experiment operations, and to
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encourage physics analysis.
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\subsection{Binary metrics}
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\begin{itemize}
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\item Automatic FEVT+AOD transfer Tier-0 to Tier-1 via PhEDEx, the
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data placement tool
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\item Automatic transfer of part of FEVT+AOD Tier-1 to Tier-2 via PhEDEx
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\item Offline DB accessible via FroNtier/Squid (a caching layer
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between the reconstruction jobs and the Oracle DB) at participating sites
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\item Insertion and use new constants in Offline DB
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\item User submission of analysis/calibration/skim jobs via the grid
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job submission tool CRAB and using the developed Dataset Bookkeeping
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Service (DBS)
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and Data Location Service (DLS)
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\item Skim job output automatically moved to Tier-2 via PhEDEx
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\item Running re-reconstruction-like jobs at Tier-1 that access
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updated information from the offline DB and perform a new
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reconstruction on data distributed fromt he Tier-0 centre
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\end{itemize}
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\subsection {Quantitative metrics}
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\begin{itemize}
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\item Number of participating Tier-1 -- Goal: 7 -- Threshold: 5
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\begin{itemize}
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\item Passing requires 90\% uptime, or $<3$ days downtime during challenge
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\end{itemize}
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\item Number of participating Tier-2 -- Goal: 20 -- Threshold 15
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\item Weeks of running at sustained rate -- Goal: 4 -- Threshold: 2
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\begin{itemize}
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\item This will be the period over which we measure the other metrics
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\end{itemize}
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\item Tier-0 Efficiency -- Goal: 80\% -- Threshold: 30\%
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\begin{itemize}
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\item Measured as unattended uptime fraction over 2 best weeks of the running period
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\end{itemize}
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\item Running grid jobs (Tier-1 + Tier-2) per day (2h jobs typ.) -- Goal: 50K -- Threshold: 30K
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\item Grid job efficiency -- Goal: 90\% -- Threshold: 70\%
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\item Data serving capability at each participating site : Goal 1MB/sec/execution slot -- Threshold : 400 MB/sec (Tier-1) or 100 MB/sec (Tier-2)
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\item Data transfer Tier-0 to Tier-1 to tape -- Individual goals (threshold at
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50\% of goal):
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\begin{itemize}
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\item ASGC: 10MB/s
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\item CNAF: 25 MB/s
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\item FNAL: 50 MB/s
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\item GridKa: 20MB/s
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\item IN2P3: 25MB/s
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\item PIC: 10 MB/s
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\item RAL: 10MB/s
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\end{itemize}
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\item Data transfer Tier-1 to Tier-2 -- Goal: 20MB/s into each Tier-2 -- Threshold: 5MB/s
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\begin{itemize}
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\item Overall ``success'' is to have 50\% of the participants at or above goal and 90\% above the threshold
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\item Several Tier-2s have better connectivity and we will have higher targets for those
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\item Goal for each Tier-2 is to demonstrate 50\% utilization of the WAN to the best connected Tier-1
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\begin{itemize}
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\item list was defined after SC4
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\end{itemize}
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\end{itemize}
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\end{itemize} |
