2023-12-07 Meeting Notes

Owned by James Walder
Last updated: Dec 08, 2023
3 min read

 Date

Dec 7, 2023

 Participants

  • @Thomas, Jyothish (STFC,RAL,SC)

  • @Thomas Byrne

  • @Alexander Rogovskiy

  • @James Walder

  • Lancs: @Matt Doidge, Gerard, Steven

  • Glasgow: Sam

Apologies:

cc. @Alastair Dewhurst

 

 

 Goals

  • List of Epics

  • New tickets

  • Consider new functionality / items

  • Detailed discussion of important topics

  • Site report activity

 

 Discussion topics

Current status of Echo Gateways / WNs testing

Recent sandbox’s for review / deployments:

 

Item

Presenter

Notes

 

Item

Presenter

Notes

 

Deployment plan and changes anticipated before Christmas

@Thomas, Jyothish (STFC,RAL,SC)

Change freeze ~ today.

new gateways awaiting updated AAAA

the bug fix (below)
manager ping

 

bugfix for calculating striper objects in direct reads

 

https://github.com/stfc/xrootd-ceph/pull/50

Any further comments on the PR; or ready to merge ?

@Katy Ellis to confirm a successful file dump read.

 

Gateway: observations and changes

@Thomas, Jyothish (STFC,RAL,SC)

Change the CMSD configuration to increase the frequency of load reporting / calculation

 

 

 

Checksums fixes

@Alexander Rogovskiy

Deployment appears to improve that metadata retrieval time at the checksum app layer, but not from the user client layer …




 

 

 

Prefetch studies and WN changes

@Alexander Rogovskiy

New tests with xrootd.async segsize 8m timeout 300 and pfc.prefetch 0. With timeout increase “prefetch off” configuration looks better than the current one.

 

Deletion studies through RDR

@Ian Johnson

Requirements from ATLAS VO (Alessandra): 11266 deletions/h of 3GiB files. We are mean seeing deletion times for 3GiB files of 0.5 - 4 seconds, however there are some large outliers. (Taken from 10 deletions of 3GiB batches, 500 files in each batch).

Current deletion times to delete a batch of 500 3GiB files average around 30s (with some large outliers, however). Extrapolating from the average would suggest a bulk deletion rate of 60,000 files per hour is achievable within RAL, using the CERN deletion timing program. It would be instructive to find test whether the deletion mechanism that ATLAS will use during DC24 (FTS?) is able to achieve acceptable deletion rates.

An example of the variation in range of deletion times (plots from 07:30 this morning and 11:40):

 

 

Tokens testing

@Thomas, Jyothish (STFC,RAL,SC) @Katy Ellis

https://stfc.atlassian.net/browse/XRD-63

can either have SAM tests passing OR the correct set of permissions.

scitokens.trace probably doesn’t alter the results now.

 

SKA Gateway box

@James Walder

https://stfc.atlassian.net/wiki/spaces/UK/pages/215941180

Deneb-dev now connected to the xrootd01 box.
A few ad-hoc tests tried. Will be starting to run for systematic tests.

 

WN Xcache issue

 

futex lock hard locking xcache proxy on WNs (possibly occurrence of https://github.com/xrootd/xrootd/issues/1979 )

 

 

on GGUS:

Site reports

Lancaster - Planning purchase of more gateways - trying to decide between single or dual CPU and would appreciate views on that.

Glasgow -

 

 

 

 Action items

  •  

 

 Decisions