RAL Tier1 Experiments Liaison Meeting

Wednesday 23 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 again, Katy is at CERN for CMS computing week and will not join the meeting.

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. 

Last week I reported the certificate version of the CVMFS test appears to not be running intermittently. Can't see this issue elsewhere. In fact it is most likely timing out. On reflection, this is probably related to the Brazil problem as above.

Job performance looks good. Bit of a spike on Tuesday morning in job failures, but these are analysis. 

13:45 → 13:50 LHCb Operations Report

Speaker: Alexander Rogovskiy (Rutherford Appleton Laboratory)

Operational issues:

• CERN IT accidentally deleted a couple of LHCb databases yesterday. Luckily, all was recovered quickly, but services were affected (e.g. we have increased failure rate accross the grid as a result);
• Problems with transfers from RAL to QMUL last week
  • QMUL issue -- incorrect SRR reporting causes DIRAC to write data to a full storage
• MCSimulation job failures due to CPU limit excess
  • Still present
• LHCb flooded arc-ce0[12] with certification jobs
  • Issue with LHCbDirac certification, submission stopped.

13:50 → 13:55 ALICE Operations Report

Speaker: Alexander Rogovskiy (Rutherford Appleton Laboratory)

mlsensor deployed to ceph-gw12 yesterday.

13:55 → 14:00 LSST Operations Report

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

14:00 → 14:01 Tier-1 Projects

14:05 → 14:10 XRootD Development

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

/store deletion issue
     this was a stub file put in place to stop recursive folder creation until cms tries to access /
     the filelist dumps have been amended to skip this file

FTS link concurrency tests

https://docs.google.com/spreadsheets/d/17OwmTx89FGTHik0wZmKjMiw3y5lNtAGEWCbNAHw1rWo/edit?gid=219734934#gid=219734934

OSG collector to be tested at RAL

    rpms received

alice package repo found and needed packages compiled for xrootd 6 upgrade

lsst interested in testing an s3 pool exposed trough xrootd

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 AOB

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 23 September 2026.docx

Weekly Report 23 September 2026.pdf

15:00 → 15:05 Any other Business

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