xrdcp fails when redirected for current versions

[RHofsaess]

Hi all,
We currently have problems with xrdcp for our local resources.
We have a XRootD server and redictor on a ceph node to provide local datasets of our users to the (external) worker nodes of our T3 via XRootD.

Setup:
Ceph configs: data server, redirector

On the worker node, a caching proxy and a redirector are running. Configs: proxy, redirector

The client is configured to use the redirector. Config: client-plugin-proxy.conf

What we observe
xrdcp fails for current versions (tested with: 5.5.1)

What we see is that the final url is build up correctly (final_url=root://f03-001-110-e.gridka.de:1094//root://ceph-node-j.etp.kit.edu:1094//mschnepf/data_mnist-tar.gz), but the transfer somewhat fails with the error:

[0B/0B][100%][==================================================][0B/s]
Run: [ERROR] Operation is not implemented:  (source)

Full log: transfer_5-5-1.log

With older versions of xrootd, however, our setup works fine, see transfer_5-3-1.log.

I tracked it down to the client(config) or the redirector.
If I do not use the redirector but ask the server directly, it works with a current xrootd version (5.5.4). Log: transfer_5-5-4-without.log

What I also observed was that changing the major version in "lib =libXrdClProxyPlugin-V.so" in the client plugin conf
does not have any influence. When changing it to V=1000, the redirect still works (and it still fails :D).
Just wanted to make sure that this behaviour is intended.

Maybe also our configs may aren't compatible with newer versions. If so, thanks for any help in advance to fix it! :)

Thanks and cheers

[smithdh]

Thanks for the report. It look as if this may be a problem with the libXrdClProxyPlugin.

To help confirm that I am seeing the same problem with xrdcp as you, please could you check that the coy does work if you run the xrdcp command with XRD_CPUSEPGWRTRD=0 set in the environment? e.g.

XRD_CPUSEPGWRTRD=0 xrdcp ...

[RHofsaess]

Yes, this works!
Tested with version 5.5.1

[smithdh]

Hi. I've opened a PR to fix the issue. So assuming there are no unexpected problems, there should be a fix in the release. In the mean time do you think you can work around this problem?

[RHofsaess]

Thanks a lot! This was fast :D
Yes sure, we will tell the users to set the env variable.
Or could disabling the in-fly error correction cause any problems?
Then, we will just fix the version to an older one.

Again thanks for the fast intervention!

PS: should I close the issue or will it be closed with the PR automatically?

[smithdh]

Hi. Ideally you'd likely want the benefit of the error correction, but in version 5.3.1 xrdcp didn't support that feature; so either disabling with the env variable or using the older client is the same in that respect. There might be some other fixes or new features in the client you'd like, which could be a reason to keep using the most recent but use the env variable.

I think we will probably close the ticket when the PR is merged!