Week of 171106

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: Julia (WLCG), Kate (chair, DB, WLCG), Maarten (ALICE, WLCG), Ivan (ATLAS), Vincent (security), Paul (storage), Gavin (computing), Alberto (monitoring), Andrea M (MW), Vladimir (LHCb), Marian (network)
  • remote: Marcelo (CNAF), Kyle (OSG), Onno (NL-T1), Christoph (CMS), Di Qing (TRIUMF), Dimitri (KIT), Dave M (FNAL), Gareth (RAL), Xin (BNL), Pepe (PIC), Ulf (NDGF)

Experiments round table:

  • ATLAS reports ( raw view) -
    • Average of ~280k cores
    • T0 backlog stays the same due to LHC duty cycle
    • Backlog to T0 Tape / Export traced back to a slow FTS node. Fixed.

  • CMS reports ( raw view) -
    • Again a busy week with ~200k CPU cores in use
    • We have still some transfer backlog
      • Mostly to KIT and FNAL (where at least the later appears to go down)
    • Ask several sites to switch away from CERN FTS server - in agreement with CERN FTS team
      • All US sites should use FNAL FTS service
      • Some European sites should use RAL FTS service
      • Several sites switched to CERN FTS after some problems or the recent down time at RAL

  • ALICE -
    • High activity on average
    • CERN: CASTOR instabilities have remained manageable
      • Today the default pool has been enlarged with disk servers borrowed from EOS - thanks!

  • LHCb reports ( raw view) -
    • Activity
      • Monte Carlo simulation, data processing and user analysis
      • Validation for restripping completed; waiting response
    • Site Issues
      • T0:
        • User had incorrect mapping at EOS; fixed
      • T1:
        • NTR
Maarten suggested LHCb open a ticket concerning the mapping issue in order to collect improvement feasibility data.

Sites / Services round table:

  • ASGC: ntr
  • BNL: NTR
  • CNAF: We have a water leakage in the data center that forced us to move a couple of machines to another part. The farm is up but some disks needed to be moved affecting CMS who may not be able to reach some files.
  • EGI: NC
  • IN2P3: NC
  • JINR: SAM srm errors on srm-cms.jinr-t1.ru. Under investigation. Seems it was due to LAN problem or DDoS attack on the service.
  • KIT: NTR
  • NL-T1: NTR
  • NRC-KI: NC
  • OSG: Belle2 VO will be added to ticket exchange machinery
  • PIC: Reminder for the downtime tomorrow for dCache and tape
  • RAL: Planning patching of Castor systems next week. Details to be confirmed.

  • CERN computing services: NTR
  • CERN storage services: NTR
  • CERN databases: Repetitive issues with CMSONR ADG, we are working with Oracle Support to trace the issue. A new standby will be prepared.
  • Monitoring:
    • Draft SAM Report for October distributed. Sites should send corrections to the VO within 10 days.
  • MW Officer: NTR
  • Networks: NTR
  • Security: EGI SVG CRITICAL risk vulnerability concerning Slurm:
    • Critical vulnerability (privilege escalation) affecting Slurm deployments with prolog/epilog deployed/configured


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Topic revision: r18 - 2017-11-06 - MaartenLitmaath
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