Performance testing the transfer accelerator plugin on orthanc 1.5.6

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1

Hi all,

We’re running performance tests of the Orthanc to Orthanc communication and in this specific case we’re loading 10 large studies onto 10 orthanc instances each and asking them to simultaneously forward all to a single “central” orthanc instance (hence attempting to sending it 100 studies more or less in parallel). Smaller volumes have worked ok, but now we seem to be hitting some sort of overflow and the application stops scaling nicely.

The behaviour observed is that the central orthanc system simply stops responding under this load and the sending orthanc instances receive multiple 404 errors back.
The central orthanc instance log has thousands of entries looking like this:

E0411 11:02:45.092245 PluginsErrorDictionary.cpp:111] Exception inside the plugin engine: Unknown resource
E0411 11:02:45.197862 PluginsErrorDictionary.cpp:111] Exception inside the plugin engine: Unknown resource
W0411 11:02:45.606946 PluginsManager.cpp:168] An inactive push transaction has been discarded: a40e2c99-1ad8-4850-8f31-e3a056fb546f
E0411 11:02:45.631551 PluginsErrorDictionary.cpp:111] Exception inside the plugin engine: Unknown resource
E0411 11:02:45.964178 PluginsErrorDictionary.cpp:111] Exception inside the plugin engine: Unknown resource

Does anyone know how to troubleshoot the very generic error message “Exception inside the plugin engine: Unknown resource”?

regards,
Pär
www.cmrad.com

2

Hello,

You should set the “MaxPushTransactions” configuration option of the plugin to a value that corresponds to the number of simultaneous transfers (at least 10 if I understand correctly your setup):
http://book.orthanc-server.com/plugins/transfers.html#advanced-options

In your case, the 404 error indicates the fact that some push transaction was discarded by the central server.

Sébastien-