1. LHCbComputing Update of LHC experiments Computing & Software Models Selection of slides from last week’s GDB http://indico.cern.ch/conferenceDisplay.py?confId=197803

2. Background Requested by the LHCC in December: need to see updated computing models before Run 2 starts A single document to: - Describe changes since the original TDRs (2005) in Assumptions, models, technology, etc. - Emphasise what is being done to adapt to new technologies, to improve efficiency, to be able to adapt to new architectures, etc. - Describe work that still needs to be done - Use common formats, tables, assumptions, etc 1 document rather than 5 March 6, 2013 Ian.Bird@cern.ch2

3. Timescales Document should describe the period from LS1 – LS2 - Estimates of evolving resource needs In order to prepare for 2015, a good draft needs to be available in time for the Autumn 2013 RRB, so needs to be discussed at the LHCC in September:  Solid draft by end of summer 2013 (!) March 6, 2013 Ian.Bird@cern.ch3

4. Opportunities This document gives a framework to: - Describe significant changes and improvements already made - Stress commonalities between experiments – and drive strongly in that direction Significant willingness to do this Describe the models in a common way – calling out differences - Make a statement about the needs of WLCG in the next 5 years (technical, infrastructure, resources) - Potentially review the organisational structure of the collaboration - Review the implementation: scale, quality of service of sites/Tiers; archiving vs processing vs analysis activities - Raise concerns: E.g. staffing issues; missing skills; March 6, 2013 Ian.Bird@cern.ch4

5. Draft ToC Preamble/introduction Resource needs and expected evolution Technology review and outlook Challenges – the problem being addressed - Consequences for computing Experiment computing models Distributed computing Computing services Common software activities and strategies Collaboration organisation and management March 6, 2013 Ian.Bird@cern.ch5

6. 6 Experiment specific chapters Many topics need to be covered in this document: - Data models – types of data, event sizes, relationships, etc. The operational workflows are strongly correlated to these. - Data flows, replication and placement policies. Optimal use of resources to provide the best possible physics throughput. Role of Tiers and sites with emphasis on functionalities and services required. - Anticipated event rates and data streams in Run-2. - Non-event data handling. For example evolution of database usage and technologies, e.g. Oracle, Frontier, Hadoop, CVMFS... - Software evolution. Further software optimization in terms of processing speed, event sizes, parallelization etc..  Data preservation. -... and several more.. An important point is to demonstrate clearly also the progress we made from the Computing TDRs until now, not just the envisaged progress towards Run2. Also, clearly identify the envisaged commonalities between experiments and potential input from the wider scientific community.

7. 7 Status m Drafts of all chapters in preparation o Bernd Panzer, Ian Bird, John Harvey o 4 LHC experiments computing projects m Experiment specific chapters based on common template o I am drafting the LHCb chapters m First drafts to be circulated within working group by end of next week o We are late, unclear if I can circulate internally first P Time for discussion and refinement during June but basically frozen by mid-July o I would have preferred to have an LHCb editorial team, but: P We are all so busy and time is short P Requires weekly F2F interaction with other experiments