"Max out keepalive_timeout for performance"

"Max out keepalive_timeout for performance"
High keepalive (like 75s) holds a worker slot open per idle client. On a low-connection box behind a CDN, that's slots wasted on browsers doing nothing.
If Cloudflare/a CDN fronts you, the CDN keeps connections to users — your origin only talks to the CDN. Tighten it:
— keepalive_timeout 15; at origin
— add upstream keepalive to PHP-FPM instead, that's where reuse pays
Match keepalive to who's actually connecting. Try it tonight.