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Minutes16Apr2010 - RAC core team minutes, April 16, 2010


Core Team Participation

Richard Mount, Jim Cochran, Michael Ernst, Kaushik De

Other Participants

Armen Vartapetian, Ian Hinchliffe, Mike Tuts

Minutes of the April 9 Meeting

Approved

Report from the CREM Meeting

Armen had attended the CREM meeting which was held entirely by phone and had struggled to achieve a quorum. See http://indico.cern.ch/conferenceDisplay.py?confId=91469 for the agenda. The principal topic was the deletion policy, final approval of which was postponed to the next meeting. The draft policy has a worrying statement that "Replica reduction is started if free disk space is less than 100TB or less than 40% of total disk space". The apparent consequence is a requirement that some facilities provide about 67% [(100/60-1)*100%] more disk space than ATLAS occupies with data.

RAC members agreed that while the implementation of the policy would certainly minimize wastage of space, text like this could give rise to misunderstandings, especially with funding agencies. The way forward was to promote informal discussion with ATLAS colleagues of how best to describe a responsible approach to maintaining adequate disk headroom.

The CREM also discussed the automation of the approval of DaTri requests. Alexei agreed to draft some rules.

Progress on "Additional Production"

Jim pointed the RAC at Kevin's draft "Resource Request" Twiki that was intended to guide physicists in requesting additional production. It was agreed that the draft could benefit from a more detailed description of the steps involved in the production, for example the role that Borut appears keen to play in managing the request list. Key input to the Twiki will be generated when Kevin runs Exotics production requests through the process.

AOB

  1. Richard will initiate a new Doodle poll for the time of the RAC meeting.
  2. The issue of making only the most recent six ATLAS releases available on the Grid was raised (has been recommended by David Rousseau). All agreed that this was counter to experience in large experiments - graduate students needed releases to be available for long periods, often years. Kaushik noted that the US has successfully requested that it be allowed to maintain older releases.
  3. Kaushik noted that ATLAS central production had exhausted its official request list recently. After a gap of 7 to 8 hours, Borut had taken a request for another 40M events out of "his back pocket", but beyond this the central request list was empty. Clearly, "Additional Production" requests are needed! In response to a "what about the Wisconsin request" question, Kaushik said this had not yet been run and that he would discuss with the originators how to ensure that this request produced valid Additional Production.
  4. Kaushik noted that MWT2 had commissioned new storage and now offered the full pledged resources (Michael noted that AGLT2 also met the full pledge). This change would require a re-balancing of the fractions distributed to the tier 2s, but Kaushik was not quite ready to propose the exact numerical values. It was agreed that such balancing was essentially an operations-driven decision. The RAC should be informed, but action should not wait for RAC meetings unless the decision was known to be contentious.

Action Items

  1. 4/9/2010: Kaushik, try to find out who is generating the large minimum bias load seen by BNL. Kaushik reported that the load seemed to come from "all over the world" reflecting wide interest in analyzing these data. (Completed)
  2. 4/9/2010: Kevin, Create first version of a Twiki guiding US physicists on requesting Additional Production. The first version was discussed.
  3. 3/26/2010: Richard, Further publicize "US Regional Production: Summary of ATLAS Policy and US Practice" (Item superseded by the ongoing discussions of Additional Production. Item will be dropped).
  4. 3/26/2010: All but especially core team, Find time during the ADC Workshop next week to identify a point-of-contact for Valid US Regional Production (on hold pending a better definition of what this task should be following successful completion of some Exotics Additional Production).
  5. 3/26/2010: Kaushik, Make formal request to the DQ2 team for a tool to display a record of what has been deleted when. (Completed)
  6. 2/12/2010: Richard Non-urgent simulation tasks - consult with physics groups on the best way to establish two-way communication with the RAC to meet this and other needs (Largely complete and/or superseded by developments - RAC core team approves dropping this item.)

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