In T152216#2966802, @EBernhardson wrote:

I have some suspicion beta is misconfigured, but not sure what or how it should be. Since starting the initImageData.php job the jobs are sending messages to logstash like:

FSFileBackend::doPrepareInternal: cannot create directory /srv/mediawiki/php-master/images/thumb/f/f9/Joo_Chia...

sample

The logged errors are (FileOperation channel):

mkdir(): Permission denied
No such file or directory
FSFileBackend::doPrepareInternal: cannot create directory /srv/mediawiki/php-master/images/thumb/<some file>

so this seems like a simple directiry permission issue.