2.8 - editor file uploads globally lock up PHP
I had this issue in older versions of Vanilla too.
As I understand it, the issue is that the upload function call in editor initialises a session, and session resource locks are global, so if a user with a slow connection initiates an upload, while that upload is in progress the whole site becomes unresponsive for all other users.
This is very much in areas of php that I don't understand very well and given that many forums probably allow file uploads, surely there's a workaround. My server config is Ubuntu 18.04 LTS with Apache running PHP 7.2 via FPM. While PHP is locked up, static resources remain available as normal.
This Stack Overflow question is describing the same issue: https://stackoverflow.com/questions/5705211/apache-uploading-a-file-freezes-my-website
Happy to dump more info on request, just not sure what is relevant here.