Last modified 2 years ago Last modified on 01/29/19 15:02:08

dCache Tier I meeting January 29, 2019

[part of a series of meetings]

Present, IN2P3(), Sara(), Triumf(), BNL(), NDGF(Jens), PIC(), KIT(Samuel), Fermi(), CERN()


(see box on the other side)

Site reports


Things going as expected.

WebDAV door performance issues

issue -- fall-out webdav door problem.

Narrowed it down to two causes

Problem #1: the door in use was a non-redirecting door. This proxied all the transfers. With a distributed setup, this hurts badly.

See approximately 10x performance boost from redirected.

Problem #2: arccp for doing the copies. As it turns out, they use byte-ranges.

URL option to disable this "feature". Disabling this gives ~5x improvement boost.

The new version, arc v6, will have this disabled by default.

Also tried this with the gfal-copy command.

With non-partial GET, gfal-copy and arccp are about

467 MiB/s

arccp partial GETs, non-redirecting door 4 MiB/s


Everything is running fine.

SRM space accounting discrepancy

Talking about bug report by ATLAS, where rucio and SRM give different space usage. Discrepancy was due to a bug in Rucio.

Unreliable transfers with China

Transfers failing between China for GridFTP.

Big files ~25 GiB files

The onWrite option was 'on', now switched 'off'.

SSH admin interface

Reminder: RT 9418

Support tickets for discussion

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Same time, next week.