WLCG DOMA BDT Meeting

Wednesday 5 Apr 2023, 16:30 → 17:30 Europe/Zurich

Brian Paul Bockelman (University of Wisconsin Madison (US)), Maria Arsuaga Rios (CERN), Petr Vokac (Czech Technical University in Prague (CZ))

Topic: WLCG DOMA BDT Meeting (twiki)

1 News

XRootD and FTS Workshop

• FTS and Tokens
  • storage.read, storage.write, storage.overwrite?!?!
    • discussion was more generic not exactly about WLCG profile
  • this will be mapped in WLCG profile to
    • storage.write -> storage.create
    • storage.overwrite -> storage.modify
  • three tokens for job submission
    • access token used to submit transfer
    • access token for source
    • access token for destination
  • use token exchange to refresh access tokens for for queued / running FTS transfer
    • FTS needs client registration with enable token exchange flow for each supported issuer
    • cache valid access tokens to limit load on token issuer
      • efficiency depends on granularity
      • e.g. AT with storage.read:/ can be reused by all transfers with same audience
      • e.g. AT with storage.create:/full/path/to/destination/file can't be really reused
    • AT are opaque to the FTS, token issuer must be configured to issue fresh AT with same storage.* content using token exchange flow
• FTS Planning Session
  • timeouts & slow / no progress? e.g. DMC-1278
    • what happens on active party side when FTS drop connection to stuck transfer
      • should we ask for HTTP-TPC improvement / clarification?
      • write email to the TPC/BDT mailing list
    • this is already well defined in HttpTpcTechnical specification
      • nothing to discuss => no mail to TPC/BDT mailing list
      • updated related DMC-1278

2 Tape REST access

Speaker: Mihai PATRASCOIU (CERN)

Optimal dCache TAPE REST configuration

• related discussion in GGUS:160869#update#31
• default dCache 8.2.19 TAPE REST request configuration is not compatible with default FTS numbers
  • FTS default parameters
    • StagingBulkSize=200
    • StagingConcurrentRequests=5000
  • dCache default parameters
    • Maximum concurrent (active) requests     :        110
    • Maximum requests per user                :         10
    • Maximum expansion depth                  :     TARGET
    • Maximum flat targets                     :     100000
    • Maximum shallow targets                  :        100
    • Maximum recursive targets                :          1
  • mismatched configuration can lead to dCache TAPE REST response
    • {  "detail": "Too Many Requests",  "title": "Too Many Requests",  "status": "429" }
• wlcg-doma-tpc email thread "FTS values for Staging Request size and Concurrent Staging Requests"
  • make reasonable defaults in future dCache releases that will be compatible with FTS default expectations

storage.stage

• no tape operations (with tokens) for DC24
• current definition of storage.stage in WLCG profile
• write email to the developers & bdt mailing list
  • clarify what needs to be implemented
  • https://newdle.cern.ch/newdle/wH9w6vf7

 

 

3 Transfers with tokens

Speaker: Francesco Giacomini (INFN CNAF)

We need documentation for site admins, because they are starting discussion in the storage support channels with questions how to "configure tokens". This is still work in progress, but CMS is converging to the recommended configuration and once it is ready it'll be advertised via wlcg-doma-bdt mailing list.

 

4 Packet marking

Speakers: Marian Babik (CERN), Shawn Mc Kee (University of Michigan (US))

5 WebDAV Error Message Improvement Project & unified error message format

Discuss with experts improvements in the error messages produced by failed transfers.
https://twiki.cern.ch/twiki/bin/view/LCG/WebdavErrorImprovement

Speaker: Stephan Lammel (Fermi National Accelerator Lab. (US))

6 AOB