I am a happy user of mod_scgi. For the in-house web apps we develop, concurrent overlapping requests involving SCGI have been a non-issue sofar. This would change for sure as soon as the web apps are exposed to the internet. But in our custom SCGI backend resp. the application logic written in Lua, almost no provision for locking shared resources such as files open for writing exists sofar.by nginx_zurich - Nginx Mailing List - English