I would like any hints or ideas as to what might be causing the following situation.
The website is on a Debian server with nginx 1.6.2, php5 through fpm.
A GET request to a page is supposed to generate a ZIP archive of considerable size from a few requested files that are on the server. It's a resource demanding operation, taking about 30 seconds (let's say) and consuming ~500+MiB of memory.
Now if during that operation the client attempts to open another page, the PHP's session handling will impose a delay for that page to open until the first GET request is finished. All this is within my understanding up until now.
However: if the client (insistently) refreshes the browser several times (5-8) the server will not respond at all to ANY user, not just the insistent one. This bugs me because the nginx configuration is set to 2
worker_processes, each with 1024
worker_connections, which should give me at least about 1000 connections before the server goes bunkers.
Top command reveals little CPU load.