Page Comparison

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\uD83D\uDC65 Participants

• James Walder

• Ian Johnson

• Glasgow: Sam

• Lancs: Steven, Matt, Gerard

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\uD83D\uDDE3 Discussion topics

Major themes of 2022 → 2023:

(non exhaustive list … )

• Bug fixing

• New release testing

• ReadV improvements (writeV ?)

  • Attempted removal of locking for read operations

  • buffering / circumvention (rewriting) of parts of libradosstriper

• Read/Write (buffering) improvements

  • Added basic IO buffering

  • Additional functionality to be added

• Deletion improvements

  • unified configuration allowed for concurrent deletes

  • need for offloading of deletes for asynchronous support ?

• Stat improvements

  • Time for “entropy” in key creation hypothesised for slow root CLI stats

  • No actual xrootd improvements needed?

  • changed from st_dev =0

  • Susceptible to heavy-IO ceph workloads (e.g. adding in SNs)

  • Susceptible to ‘bad’ behaving Gateways

• Checksum improvements

  • Checksum requests:

    • python script creates a unique rados client connection for each request => slow metadata retrievals

      • client/server model ~ 8x faster

  • Checksum calculation:

    • Done post-transfer, single read thread

      • Demonstrated ‘concurrent’ per-file checksumming

    • Work ongoing (Glasgow) on in-flight checksumming

    • OSD-based checksumming would remain an interesting topic (could deletions also be a use case?).

• Spaceinfo:

  • allow for spaceinfo (used / quota) space ongoing

• Token support:

  • Macaroons supported

  • WLCG profile tested and (mostly) passing

    • Still to be enabled in Prod (and for real VOs)

• Configuration:

  • External gateways: replaced memory cache with internal buffering

    • Fixed namelib code in XrdCeph

    • Created Unified configuration

      • Added TPC xrootd (to allow for xrootd writes)

  • Combined the xrootd and webdav aliased hosts to (mostly) common set.

  • CMSD to be deployed

    • Testing on prod on-going

    • Need VM hosts

  • WNs:

    • Move to more updated version

    • ‘fix’ readVs

    • Need the Xcache still ?

    • Other plans ?

Open Epics

Jira Issues not within an Epic

https://stfc.atlassian.net/jira/software/c/projects/XRD/boards/26/roadmap

Item	Presenter	Notes
Combining xrootd and webdav aliases gateways		LHCb started ~O(500)TB Data challenge from cern EOS to Antares; Almost all data going via Echo. https used for each transfer link. “External view” of RAL incoming / outgoing connections Image AddedImage Added Snapshot of “Best period” of eos->Echo transfers ~ 900 concurrent transfers @ ~ 3.26GB/s Image Added “Best plot” with Echo to Antares; reached ~ 7.4GB/s. A lot more “bursty” set of transfers. Image Added ATLAS; has ~ 130k FTS backlog of writes into Echo svc97 Image Added
Alice space token development updates		https://stfc365-my.sharepoint.com/:w:/r/personal/ian_johnson_stfc_ac_uk/_layouts/15/Doc.aspx?sourcedoc=%7B132F553F-27B6-45AB-9020-41504A5F957B%7D&file=ECHO%20Disk%20Space%20Reporting%20Requirements.docx&wdLOR=cCFF7C51D-DE6D-D448-B9AC-07488D1976A8&action=default&mobileredirect=true
Deletes Jira Legacy server System JIRA serverId 929eceee-34b0-3928-beeb-a1a37de31a8b key XRD-52
Jira Legacy server System JIRA serverId 929eceee-34b0-3928-beeb-a1a37de31a8b key XRD-53 Jira Legacy server System JIRA serverId 929eceee-34b0-3928-beeb-a1a37de31a8b key XRD-50		No time yet to properly investigate, but should be considered urgent.
Vector reads
tokens testbed		Lost dev-gw2 to Alice GW testing of space tokens.	Planning	Todo: Discuss / plan main roadmap for 2023

Spaceinfo reporting Current requirements document:

GGUS:

Deletion problem at RAL

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Problem accessing some LHCb files at RAL

Site reports

✅ Action items

JW to add issue to xrootd GitHub to request Expect: 100 continue functionality for XrootD checksumming.

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• Enabled the memory cache on the internal gateway (to attempt to mitigate simultaneous reads against the same file).

✅ Action items

⤴ Decisions

• Next meeting January 12th 2023