Tier1 Operations Report 2017-05-31

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RAL Tier1 Operations Report for 31st May 2017

Review of Issues during the week 24th to 31st May 2017.
  • A problem of ARP poisoning on the Tier1 network is affecting some monitoring used by CEPH ECHO. The cause of this is now believed to be understood and the fix (a setting change in the OPN Router) will be applied at the earliest practical time.
  • There is a problem on the site firewall which is causing problems for some specific data flows. This was being investigated in connection with videoconferencing problems. It is expected that this is having an effect on our data that flows through the firewall (such as to/from worker nodes).
  • Atlas carried out a large deletion test of files in ECHO last week. The bulk were deleted successfully and in a reasonable timescale. However, some (one to two thousand) files failed to delete. Most of these were cleaned up manually leaving a handful for debugging purposes. However, the system subsequently also deleted these remaining files without intervention.
Resolved Disk Server Issues
  • GDSS773 (LHCbDst - D1T0) crashed on Sunday (21st May). It was returned to service Thursday morning (25th) although not fault was found during the diagnostic testing.
  • GDSS804 (LHCbDst - D1T0) was taken out of production on Tuesday 23rd as it was showing memory errors. However, the memory tests then failed to find anything and it was returned to service the following day.
Current operational status and issues
  • We are still seeing a rate of failures of the CMS SAM tests against the SRM. These are affecting our (CMS) availabilities. CMS are also looking at file access performance and have turned off "lazy-download". This will be re-addresses once we have upgraded to Castor 2.1.16.
  • LHCb Castor performance has been OK since the 2.1.16 update although this was not under and high load. A load test (mimicing the stripping/merging campaign) was carried out last Wednesday (24th May). This was successful in that the specific problem seen before the Castor 2.1.16 upgrade had gone. The main limitations the test hit within Castor was load on the older disk servers in the instance. Following the 2.1.16 upgrade and this test I will remove this item from the list of ongoing issues.
Ongoing Disk Server Issues
  • GDSS658 (AtlasScratchDisk - D1T0) crashed yesterday afternoon (30th May). It is still undergoing tests.
Limits on concurrent batch system jobs.
  • CMS Multicore 550
Notable Changes made since the last meeting.
  • CMS Castor instance updated to Castor version 2.1.16-13 and the CMS SRMs also upgraded to version 2.1.16.
  • For LHCb Castor the xroot manager was installed on the (LHCb) stager. This resolves a problem affecting LHCb when a TURL returned by the SRM does not always work when used for xroot access owing to an incorrect hostname.
  • CEs being migrated to use the load balancers in front of the argus service.
  • Batch access has been enabled for LIGO and the MICE pilot role.
Declared in the GOC DB
Service Scheduled? Outage/At Risk Start End Duration Reason
Castor GEN instace (srm-alice, srm-biomed, srm-dteam, srm-ilc, srm-mice, srm-na62, srm-pheno, srm-snoplus, srm-t2k) SCHEDULED OUTAGE 31/05/2017 10:00 31/05/2017 15:00 5 hours Upgrade of Castor GEN instance to version 2.1.16.
Advanced warning for other interventions
The following items are being discussed and are still to be formally scheduled and announced.

Pending - but not yet formally announced:

  • Update Castor (including SRMs) to version 2.1.16. Central nameserver and LHCb and Atlas stagers done. Current plan: CMS stager and SRMs on Thursday 25th May. GEN to follow.
  • Update Castor SRMs - CMS & GEN still to do. These are being done at the same time as the Catsor 2.1.16 updates.

Listing by category:

  • Castor:
    • Update SRMs to new version, including updating to SL6.
    • Update Castor to version 2.1.16 (ongoing)
    • Merge AtlasScratchDisk into larger Atlas disk pool.
  • Networking
    • Increase OPN link to CERN from 2*10Gbit to 3*10Gbit links.
    • Enable first services on production network with IPv6 now that the addressing scheme has been agreed. (Perfsonar already working over IPv6).
  • Services
    • Put argus systems behind a load balancers to improve resilience.
    • The production FTS needs updating. This will no longer support the soap interface. (The "test" FTS , used by Atlas, has already been upgraded.)
Entries in GOC DB starting since the last report.
Service Scheduled? Outage/At Risk Start End Duration Reason
Castor GEN instace (srm-alice, srm-biomed, srm-dteam, srm-ilc, srm-mice, srm-na62, srm-pheno, srm-snoplus, srm-t2k) SCHEDULED OUTAGE 31/05/2017 10:00 31/05/2017 15:00 5 hours Upgrade of Castor GEN instance to version 2.1.16.
srm-cms-disk.gridpp.rl.ac.uk SCHEDULED OUTAGE 25/05/2017 10:00 25/05/2017 13:03 3 hours and 3 minutes Upgrade of CMS Castor instance to version 2.1.16.
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
128398 Green Top Priority Waiting for Reply 2017-05-18 2017-05-24 LHCb File cannot be opened using xroot at RAL
128308 Green Urgent In Progress 2017-05-14 2017-05-15 CMS Description: T1_UK_RAL in error for about 6 hours
127967 Green Less Urgent On Hold 2017-04-27 2017-04-28 MICE Enabling pilot role for mice VO at RAL-LCG2
127612 Yellow Alarm In Progress 2017-04-08 2017-05-19 LHCb CEs at RAL not responding
127597 Yellow Urgent Waiting for Reply 2017-04-07 2017-05-16 CMS Check networking and xrootd RAL-CERN performance
127240 Red Urgent In Progress 2017-03-21 2017-05-15 CMS Staging Test at UK_RAL for Run2
124876 Red Less Urgent On Hold 2016-11-07 2017-01-01 OPS [Rod Dashboard] Issue detected : hr.srce.GridFTP-Transfer-ops@gridftp.echo.stfc.ac.uk
117683 Red Less Urgent On Hold 2015-11-18 2017-05-10 CASTOR at RAL not publishing GLUE 2.
Availability Report

Key: Atlas HC = Atlas HammerCloud (Queue ANALY_RAL_SL6, Template 845); Atlas HC ECHO = Atlas ECHO (Template 841);CMS HC = CMS HammerCloud

Day OPS Alice Atlas CMS LHCb Atlas ECHO Atlas HC Atlas HC ECHO CMS HC Comment
24/05/17 100 100 100 97 100 100 99 99 100 SRM Test failures (user timeout)
25/05/17 100 100 100 87 100 100 100 100 98 SRM Test failures (user timeout)
26/05/17 100 100 98 98 100 100 100 100 100 SRM Test failures: Atlas: One error ‘User belonging to VO not authorized to access space token ATLASDATADISK; CMS: user timeout.
27/05/17 100 100 100 98 100 100 100 100 100 SRM Test failures (user timeout)
28/05/17 100 100 100 97 100 100 100 100 100 SRM Test failures (user timeout)
29/05/17 100 100 100 98 100 100 98 100 100 SRM Test failures (user timeout)
30/05/17 100 100 100 94 100 100 92 100 100 SRM Test failures (user timeout)
Notes from Meeting.
  • None yet.
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