My server cpu &ram running low at 30%memory and below average 10% cpu.
But server responding very slow.
Disabled acpu maybe underlying issues with php. Page cache fastcgi implemented shm 200m in ttfs. Redis installed configured with php-redis extension. As object cache
W3 total cache settings page cache; disk /redis. Object &db cache redis.
Minify &&all other ignored.
Pagespeed mod enabled.
Opcache getting errors on 7.0 upgraded 7.2. and disabled opcache and apcu. Cloudflare serves up to 70%full page cache including HTML. Php fpm set to on demand to save memory.
Rate limiting added to nginx.
May I remove w3 total cache since page cache by fast cgi & object cache by redis.
Opcodes by opcode.
Minification by pagespeed mod.
Nginx uses only 3% cpu ram. But php-fpm causing all the errors.
Still server response time is high 1 second.
How to fix? Php 7.2 Nginx 1.13.9 mainline Debian 9 Mysql latest from source.
Tweaked network and kernel settings to max performance. But still I am a newbie.