Week of 170710

WLCG Operations Call details

  • At CERN the meeting room is 513 R-068.

  • For remote participation we use the Vidyo system. Instructions can be found here.

General Information

  • 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;
    • to inform about recent or upcoming changes in the experiment activities or systems having a visible impact on sites;
    • to provide important news about the middleware;
    • to communicate any other information considered interesting for WLCG operations.
  • The meeting should run from 15:00 until 15:20, exceptionally to 15:30.
  • The SCOD rota for the next few weeks is at ScodRota
  • General information about the WLCG Service can be accessed from the Operations Web
  • Whenever a particular topic needs to be discussed at the daily meeting requiring information from site or experiments, it is highly recommended to announce it by email to wlcg-operations@cernSPAMNOTNOSPAMPLEASE.ch to make sure that the relevant parties have the time to collect the required information or invite the right people at the meeting.

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




  • local: Alberto (monitoring), Andrea (MW Officer + data management), Andrei (databases), Belinda (storage), Gavin (computing), Julia (WLCG), Maarten (SCOD + ALICE + GGUS), Petr (ATLAS), Renato (LHCb), Vincent (security)

  • remote: Alexander (NLT1), David B (IN2P3), David M (FNAL), Di (TRIUMF), Dmytro (NDGF), John (RAL), Kyle (OSG), Luca (CNAF), Pepe (PIC), Sang-Un (KISTI), Victor (JINR), Xin (BNL)

Experiments round table:

  • ATLAS reports ( raw view) -
    • Activities:
      • stable production dominated by simulation + derivation (many small output files stressed some storages)
      • ATLAS P1 to EOS to CASTOR data throughput test ( details)
    • Issues
      • CERN-PROD_DATADISK ran out of inodes (already week ago on Saturday 1.7.) - available inodes was added in monitoring
      • slow data deletion at IN2P3 -CC were caused by IPv6 broken configuration (ACL) - 2+ minutes spent by rucio to create session for file deletion (IPv6 to IPv4 connection timeout)
      • no data in ATLAS DDM Dashboard for file transfer monitoring from Wednesday evening to Friday noon caused by OpenSSL assertion while sending rucio hermes messages to ActiveMQ (INC:1404239)
      • Taiwan-LCG2 IPv6 connection issues (file transfer failures) to T1 centers in ES & FR cloud seem to be solved GGUS:129371
    • Other
      • WT2 SLAC is no longer T2 (as of October 2016) - we have to replicate primary data to the other sites

  • CMS reports ( raw view) -
    • Virtual report as I (and most others in CMS Computing) will be traveling to our Face to Face meeting in the USA.
    • Please send mails or (better) open GGUS if you have any question for CMS
    • NTR on operation, quiet week and request for resources from the physics community still on the low side

  • ALICE -
    • Very high activity on average
    • CERN:
      • ~10k jobs lost Sun ~21:30 due to ce508 crash
      • ~7k jobs lost Mon ~04:00 due to ce505 crash
      • Gavin: the hosts crashed due to an HTCondor bug; we are following up with the devs

  • LHCb reports ( raw view) -
    • Activity
      • User analysis and Monte Carlo simulation
    • Site Issues
      • T0: Jobs hold at HTCondor CEs CERN-PROD (GGUS:129147)
      • T1:
        • NTR

Sites / Services round table:

  • ASGC:
  • BNL: NTR
  • EGI:
  • FNAL: Had a GGUS ticket (GGUS:129300) not propagate correctly to OSG when opened a week ago, but did finally when updated a few days later -- See https://ticket.opensciencegrid.org/34352
  • IN2P3: NTR
  • JINR:
    • Configuration of IPv6 on SEs completed. WNs also configured for dual stack.
    • This week we will try to improve the reliability of the main link to Moscow.
    • IPv6 routing from JINR on LHCOPN need some configuration on the other sides, our network staff is working on a problem.
  • KIT:
  • NL-T1:
    • A downtime starting at 15:00 UTC this afternoon until 15:00 UTC tomorrow afternoon at SURFsara. Hardware replacement at the tape back-end. During this downtime it will not be possible to read files from tape.
  • NRC-KI:
  • OSG:
    • Kyle: will check if ticket propagation between GGUS and OSG works OK now
  • PIC: NTR
  • RAL: NTR

  • CERN computing services:
    • 5/6 July: DNS problem on our hypervisors caused 950 nodes (across HTCondor/LSF/AtlasT0) to get bad resolv.conf - most running jobs on those nodes were lost. OTG:0038529
  • CERN storage services: All CASTOR updates went ahead OK.
  • CERN databases: NTR
  • GGUS:
    • Maarten: will look into the ticket propagation issue between GGUS and OSG
  • Monitoring:
    • Draft availability reports for June distributed. One re-computation from ATLAS done.
    • Final report generated this Friday.
  • MW Officer: As discussed during the WLCG ops coord last week, we are creating 2 mailing lists for discussions around ARC-CE and HTCondor in WLCG. We will broadcast them as soon as they are ready.
  • Networks:
  • Security: NTR


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Topic revision: r15 - 2017-07-10 - MaartenLitmaath
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