Normally the Remote Reference is populated automatically after import to ColumbusPlus. However if the transfer service that transfers the data from the local storage (/OMERO/OMERO/s3-upload) to the shared file system is delayed it can lead to the Remote Reference being missing.
Typically no errors appear in the Colunbus Interface but can be found on the server in the file:
/var/log/columbus/web/long-tasks.log
A typical example might include:
(No more files to transfer but measurement.done file did not appear after 600 seconds)
It is possible to increase the 600 second transfer timeout. In the file:
/usr/local/PerkinElmerCTG/Columbus2.8/webapp/virtualenv/lib64/python2.6/site-packages/coca/transfer.py
Line 183 keep_retry_time = 600 # seconds
Increase the timeout to allow the transfer service more time to start copying files.
After editing the file restart Columbus for changes to take effect:
$ /etc/init.d/columbus restart
In versions above 2.8.2 (i.e soon to be released 2.9.0) the strategy to transfer data is changed to avoid this.