How to fix server response time issue when using Nginx and PHP7.0-FPM?

Question

PHP

Good day!
For several years, the server on Nginx (4 CPU 1GB RAM) worked without problems. But suddenly there was a problem with php-fpm because of which the sites on the server stopped working. After reinstalling the system, it was possible to raise the site's performance. But there was a problem with a long server response, and I just can’t figure out where the legs are growing from.
nginx.conf configs:

user www-data;
worker_processes auto;
pid /run/nginx.pid
events {
worker_connections 1024;
multi_accept on;
}
http {
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 30;
keepalive_requests 100;
client_body_timeout 10;
reset_timedout_connection on;
send_timeout 2;
types_hash_max_size 2048;
# server_tokens off;
server_names_hash_bucket_size 64;
# server_name_in_redirect off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
#access_log /var/log/nginx/access.log;
access_logoff;
error_log /var/log/nginx/error.log crit;
gzip on;
gzip_disable "msie6";
gzip_variable on;
gzip_proxied any;
gzip_comp_level 6;
gzip_buffers 16 8k;
gzip_http_version 1.1;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
open_file_cache max=200000 inactive=20s;
open_file_cache_valid 30s;
open_file_cache_min_uses 2;
open_file_cache_errors on;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}

site config:

server {
listen 443 default_server;
server_name mysite.com;
# Path to the folder with the code
root /var/www/mysite.com/public_html;
index index.php index.html;
ssl on;
ssl_certificate /path/to/pem.pem;
ssl_certificate_key /path/to/key.pem;
location / {
autoindex off;
try_files $uri @opencart;
}
location @opencart {
if (!-f $request_filename){
set $rule_0 1$rule_0;
}
if (!-d $request_filename){
set $rule_0 2$rule_0;
}
if ($rule_0 = "21"){
rewrite ^/([^?]*) /index.php?route=$1 last;
}
}
location ~ \.tpl {
deny all;
}
location ~* ^.+\.(js|css|png|jpg|jpeg|gif|ico)$ {
access_log off;
expires max;
log_not_found off;
}
location ~ \.php$ {
try_files $uri =404;
fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}

I didn't change anything in the php configs.
htop shows that the mysql processes are using a lot of memory, but they used to do this before, but the server responded normally.
Please help me figure out what's what.

Answer 1

Check access logs and block bots and search engines by ip. Probably the server is under load.

Answer 2

access logs look normal. First of all, I thought about the load and deployed a similar system on another server with 2GB of RAM. But the problem remained.

Answer 3

I had a similar problem with FPM, but I disabled xdebug. By the way, try running sites through the built-in PHP server: do php -S localhost:8000 in your site's DOCUMENT_ROOT and see how long the site responds from localhost. Same wget.