RAL Tier1 Experiments Liaison Meeting

Wednesday 30 Sept 2026, 13:30 → 15:50 Europe/London

Access Grid (RAL R89)

13:30 → 13:34 Site Operations

13:34 → 13:35 Experiment Operational Issues

13:35 → 13:40 ATLAS Operations Report

Speakers: Brij Kishor Jashal (Rutherford Appleton Laboratory), Jyoti Prakash Biswal (Rutherford Appleton Laboratory)

Brij ATLAS liason meeting notes

13:40 → 13:45 CMS Operations Report

Speaker: Katy Ellis (Science and Technology Facilities Council STFC (GB))

Apologies one more time, Katy is in Naples for LHCONE meeting and will not join the meeting.

From last week: On the intermittent failures on the (token version of the) CVMFS test, see https://cmssst.web.cern.ch/siteStatus/detail.html?site=T1_UK_RAL :

Alex checked it and says we are frequently contacting the Stratum-1 in Brazil. I question how often we should be contacting that host - possible issue #1. It seems that there are many retries. Asking CMS experts, they are not even aware of a Stratum-1 in Brazil. The reply from the Brazilian site shows they are a Stratum-1 for ALICE. Not many other CMS sites are seeing an error on the same test - those that are could have a different cause. Alex wondered whether there could be some issue with the network path between RAL T1 and the Brazilian site - possible issue #2. Thanks Alex for investigating. I wonder if ALCE jobs at RAL try to contact this Brazilian host? Possible solutions - fix whatever is stopping this connection with Brazil (São Paulo) or somehow stop the test trying to access it. 

Job appear to be running fine.

Note that this afternoon the WLCG VOs will present their DC27 targets at the DOMA-General.

13:45 → 13:50 LHCb Operations Report

Speaker: Alexander Rogovskiy (Rutherford Appleton Laboratory)

Operational Issues:

• The fix for the MCSimulation CPUtime issue is ready
  • Hotfixed to production DIRAC today for testing
• Issues with Manchester and QMUL storage, resulted in failed transfers from RAL to these sites.

13:50 → 13:55 ALICE Operations Report

Speaker: Alexander Rogovskiy (Rutherford Appleton Laboratory)

mlsensor deployed to ceph-gw12, it is working!

13:55 → 14:00 LSST Operations Report

Speakers: Thomas Birkett, Timothy Noble (Science and Technology Facilities Council STFC (GB))

• Data access optimisations have been ongoing over the last few weeks - with pulling in the quantum graphs (job task information) and butler.yaml files that provide information on how to access the butler database
  • • Additional optimisations were implemented and tested thanks to the XrootD monitoring from Martina, helping me identify file access counts, and timeframes highlighting highly re-used files that could be cached in the job scratch space
    • Upside more efficient jobs and Jyothish / Martina may not hunt me down as quickly when LSST run jobs
      This has led to marked inprovement in step4c of the pipelines:
      
• Changes to where and how the butler.yaml files caused some issues, that are now resolved.
• RAL continues to run jobs well for LSST - the ~100% efficiency spike is 'legacy' dc2 testing (as its run with single core jobs submitted by Panda) where all multicore jobs are now submitted by HTCondor
  
• No data move to RAL over the last 2 weeks - I will follow this up after the meeting to ensure this is correct behaviour
• VOMS change for SLAC LSST Voms server, Tom is working on the change
•  

14:00 → 14:01 Tier-1 Projects

14:05 → 14:10 XRootD Development

Speakers: Alexander Rogovskiy (Rutherford Appleton Laboratory), Jyothish Thomas (STFC)

14:15 → 14:20 Utilizing GPUs

Speakers: Dr Brij Kishor Jashal (Rutherford Appleton Laboratory), Thomas Birkett

14:25 → 14:45 Hardware deployment

Echo SN
WN
GPU

Speaker: Jacob Ward

14:45 → 14:46 DC 27

14:50 → 14:59 Summary of Operational Status and Issues

Speakers: Brian Davies (Science and Technology Facilities Council STFC (GB)), Darren Moore, Thomas Birkett

Weekly Report 30 September 2026.docx

Weekly Report 30 September 2026.pdf

15:00 → 15:05 Any other Business

Speakers: Brian Davies (Science and Technology Facilities Council STFC (GB)), Darren Moore

15:15 → 15:16 AOB