The goal of the [[ https://www.mediawiki.org/wiki/Beta_cluster | beta cluster ]] is to //"provide an exact copy of the WMF production cluster (including db hosts, apaches, logging, squids, varnish caching, image scalers, etc.) using Wikimedia Labs instances"//. In the case of image scalers, it really falls short of this goal though; the setup is not even remotely similar:
* prod is using swift to store the files, beta uses NFS
* deployment-upload is not puppetized at all (according to the [[ https://wikitech.wikimedia.org/wiki/Nova_Resource:Deployment-prep/Overview | beta config overview page ]]) so there are probably all sorts of differences in installed packages.
* prod uses custom Varnish code to redirect thumbnail misses to Swift and then to the scalers (according to [[ https://wikitech.wikimedia.org/wiki/Media_storage#Caching_proxies | (1) ]]), beta uses nginx with a 404 handler php script which is as far as I can tell not tracked in git and seems to be a modified version of a several years old revision of MediaWiki's thumb.php
* prod uses standalone image scaler servers, on beta image scaling seems to be done by the standard apache backends (deployment-upload just forwards the request to deployment-cache-text02)
... and probably more, given that the beta file server was set up a long time ago and not maintained since then.