Uploads failing on a server where the limits were already high

A client couldn't install a theme or import demo content on their own VPS. The obvious explanation was the upload limits, except the upload limits were already set high enough.

The objective

The client was building a WordPress site on a VPS and couldn't upload a theme file. Their read was that the limits were too low, and they asked me to raise all of them.

The configured limits were already high. Pushing them higher would have changed nothing, and it would have looked like a fix right up until the next upload failed.

Separately, the page builder's side panel just spun without ever loading, which the client suspected was the theme's fault.

What I did

I checked the configured limits before touching anything and told the client they weren't the cause.

I added a request body size directive to the nginx configuration and adjusted the FastCGI settings, which is where a large upload through nginx and PHP-FPM actually gets stopped.

For the panel that wouldn't load, I installed a Redis object cache so the repeated queries stop hitting the database on every request, and asked them to keep it in place.

I didn't bill for the second visit, since the first one should have finished the job.

The result

Theme uploads and demo imports went through, and the builder panel loaded. Five orders with this client across nine months.