Week of 170703

WLCG Operations Call details

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  • The purpose of the meeting is:
    • to report significant operational issues (i.e. issues which can or did degrade experiment or site operations) which are ongoing or were resolved after the previous meeting;
    • to announce or schedule interventions at Tier-1 sites;
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Tier-1 downtimes

Experiments may experience problems if two or more of their Tier-1 sites are inaccessible at the same time. Therefore Tier-1 sites should do their best to avoid scheduling a downtime classified as "outage" in a time slot overlapping with an "outage" downtime already declared by another Tier-1 site supporting the same VO(s). The following procedure is recommended:

  1. A Tier-1 should check the downtimes calendar to see if another Tier-1 has already an "outage" downtime in the desired time slot.
  2. If there is a conflict, another time slot should be chosen.
  3. In case stronger constraints cannot allow to choose another time slot, the Tier-1 will point out the existence of the conflict to the SCOD mailing list and at the next WLCG operations call, to discuss it with the representatives of the experiments involved and the other Tier-1.

As an additional precaution, the SCOD will check the downtimes calendar for Tier-1 "outage" downtime conflicts at least once during his/her shift, for the current and the following two weeks; in case a conflict is found, it will be discussed at the next operations call, or offline if at least one relevant experiment or site contact is absent.

Links to Tier-1 downtimes

ALICE ATLAS CMS LHCB
  BNL FNAL  

Monday

Attendance:

  • local: Alberto (monitoring), Andrea (MW Officer + data management), Cedric (ATLAS), Emil (databases), Hugo (storage), Julia (WLCG), Maarten (SCOD + ALICE + GGUS), Marcelo (LHCb), Marian (networks), Vincent (security)
  • remote: Chi-Hsun (ASGC), Christoph (CMS), David B (IN2P3), David M (FNAL), Elena (CNAF), Elizabeth (OSG), John (RAL), Onno (NLT1), Sang-Un (KISTI), Vincenzo (EGI), Xin (BNL)

Experiments round table:

  • ATLAS reports ( raw view) -
    • Activities:
      • Mainly simulation + derivation
      • Planned throughput test EOS to Castor on July 6-7 (this week is Machine Development)
      • Discussion last week with FTS team to change some parameters from the optimizer (summary sent to the fts3-steering mailing list). Can affect the other VOs. Would be good to have feedback.
    • Issues:
      • No major issues last week.
      • Today : problem for Sim@P1 jobs that cannot access condition DB. Problem seems to be related to network. Under investigation

  • CMS reports ( raw view) -
    • Rather moderate CPU load by CMS
      • Had some "spike" to ~100k core usage, when some big MC requests entered
    • (Too?) Frequent remote reading of RAW data from Tier-0 section of CMS EOS instance at CERN
    • Some not yet understood file reading problems at CERN EOS GGUS:129268

  • ALICE -
    • Continued high activity on average

  • LHCb reports ( raw view) -
    • Activity
      • User analysis and Monte Carlo simulation
    • Site Issues
      • T0: Jobs hold at HTCondor CEs CERN-PROD (GGUS:129147)
      • T1:
        • IN2P3: Downloads and Uploads issues during weekend, fixed

Sites / Services round table:

  • ASGC: NTR
  • BNL: NTR
  • CNAF:
    • NTR
  • EGI: NTR
  • FNAL: NTR
  • IN2P3: NTR
  • JINR: IPv6 reverse DNS broken 27-06-2017 due to operator mistake, affected data transfers and local jobs efficiency.
  • KISTI: NTR
  • KIT:
  • NDGF:
  • NL-T1: Two upcoming SURFsara downtimes (will try to combine next time smile ):
  • NRC-KI:
  • OSG: NTR
  • PIC: NTR
  • RAL: NTR
  • TRIUMF: Apology that I could not connect. We experienced namespace/Postgres performance issues after upgrading dCache to 2.16.39 last Monday. Recovered after disabling the sequential table scan.
    • Onno:
      • at NLT1 we had the same problem
      • the dCache developers then updated their upgrade guide
      • other dCache sites please ensure you consult the latest version!

  • CERN computing services:
  • CERN storage services:
    • EOSCMS:
      • Updated headnode to put new GSI plugin in production
      • T0Proxy: Being discussed with T0 people, "bad performance" comes from conservative configuration to NOT overload the headnode (this will be removed, and the proxying will probably be replaced by a redirection)
    • CASTOR upgrades foreseen this week, these involve a (transparent) software update and a diskserver reinstallation campaign (SLC6->CC7 update) with reduced capacity while the machines are down:
      • ATLAS+CMS tomorrow,
        • Also, ATLAS would like to do a full-workflow DAQ (P1->EOS->CASTOR->Tape) throughput test on Thu night, will need to temporarily increase the number of available tape drives (and lower again for "real" data taking).
      • PUBLIC on Wed.,
      • ALICE+LHCb Thu.
  • CERN databases: Alice online (ALIONR) database and OS patching will be done this week on Tuesday starting at 15:00. LHCb online (LHCBONR) and PDBR database and OS patching will be done this week on Wednesday starting at 10:00. Both interventions will be rolling, so the DBs always up, but disconnections possible.
  • GGUS:
    • since Remedy was upgraded on May 31 there have been issues with binary attachments
      • Firefox could no longer download them
      • other clients experienced a very low download speed for such attachments
      • GGUS:129153 was opened on June 26
      • the problem was fixed on June 29
  • Monitoring:
    • Final availability reports for May were sent around last week.
    • Draft availability reports for June were sent today.
  • MW Officer: NTR
  • Networks: NTR
  • Security: NTR

AOB:

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Topic revision: r15 - 2017-07-04 - JosepFlix
 
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