TYPO3 Core

Scenario: Given is a cluster of containers/servers that run multiple instances of the same TYPO3 instance. A load balancer round robins requests to those instances.

Problem: A backend user logs in and gets a broken backend. No styles and javascripts are loaded. Requests to those resources return HTTP 404 errors.

Analysis: TYPO3 concatenates assets on the fly per backend module when they are requested and saves them to a local temporary folder. As requests are routed to different containers on every request, the probability of hitting an container/server where the resulting asset is not yet generated, is very high (basically always). The only way to circumvent this, is to put the backend in debug mode, which has other unwanted sideffects.

Solution: Deactivate asset compression/concatination alltoghether for the backend. As most servers deliver HTTP2/3 nowadays, the performance impact should be minimal. By skipping unnessary processing and allowing browser caching, performance could be even increased.