Wordprees unrealistically loads the server, how to find out what is the reason?

Question

WordPress

Good afternoon,
I ran into a problem or incorrect server configuration,
I'm new in this business,
sometimes a site (on Wordpress) starts loading the server unrealistically
on the site of about 10,000 visitors a day
and it's impossible to raise the server
, basically the web server is loaded
top - 12:23 :19 up 23:42, 1 user, load average: 141.22, 140.41, 124.25
Tasks: 294 total, 135 running, 159 sleeping, 0 stopped, 0 zombie
%Cpu(s): 88.5 us, 10.8 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.6 si, 0.0 st
KiB Mem : 7879376 total, 2450180 free, 3023576 used, 2405620 buff/cache PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
KiB Swap: 2094076 total, 1935612 free, 158464 used. 4404752 availMem
2390 admin 20 0 477772 11260 4156 R 4.2 0.1 0: 51.63 httpd
2520 admin 20 0 478776 11784 4156 R 4.2 0.1 0: 49.65 httpd
2675 admin 20 0 478520 11264 4156 R 4.2 0.14 httpd 274 admin 20 0 474 httpd 274 admin 20 0 474 httpd 274
admin 20 4.2 0.1 0: 43.76 httpd
2753 admin 20 0 479800 12576 4156 R 4.2 0.2 0: 46.31 httpd
2795 admin 20 0 479544 12320 4156 R 4.2 0.2 0: 44.52 httpd 2843 admin 20 0 478776 11724 4156 R 4.2 0.1 0: 42.63 httpd 2845 admin 20 0 479032 11992 4156 R 4.2 0.2 0:41.46 httpd 2847 admin 20 0 520580 56104 5328 R 4.2 0.7 0:40.98 httpd
2836 admin 20 0 478520 11460 4156 R 4.2 0.1 0:40.41 httpd
2837 admin 20 0 475968 9184 4156 R 4.2 0.1 0:40.30 httpd
2861 admin 20 0 476220 9492 4156 R 4.2 0.1 0.19 httpd
2870 admin 20 0 475984 9112 4160 R 4.2 0.1 0: 40.48 httpd
2874 admin 20 0 478520 11200 4.2 0.1 0.1 httpd
2876 ADMIN 20 4.2 0.1 0: 40.45 httpd
2874 admin 20 0 480824 13316 4160 R 4.2 0.2 0:41.63 httpd
2881 admin 20 0 478264 10936 4160 R 4.2 0.1 0:41.70 httpd
2883 admin 20 0 478776 11720 4152 R 4.2 0.1 0: 40.53 httpd
2887 admin 20 0 479544 12520 4160 R 4.2 0.2 0: 38.70 httpd
2888 admin 20 0 478776 11460 4156 R 4.2 0.1
0 4.2 0.1 0: 42.15 httpd
3175 admin 20 0 478264 11188 4148 R 4.2 0.1 0: 28.31 httpd
32308 nginx 20 0 97592 32552 1116 S 4.2 0.4 3: 20.54 nginx
20 0 80072 15332 1116 S 4.2 S 4
20 0 390068 9784 1152 S 2.1 0.1 0:00.21 named
2351 admin 20 0 514148 49884 5236 R 2.1 0.6 0:56.66 httpd
2352 admin 20 0 479800 12576 4156 R 2.1 0.2 0: 54.35 httpd
2355 admin 20 0 480824 13368 4156 R 2.1 0.2 0: 56.39 httpd
2359 admin 20 0 525980 61412 5392 R 2.1 0.8 0:
57.7.7 2.1 0.7 0:52.53 httpd
server
specifications centos7 ngnix+apache
Intel(R) Xeon(R) CPU X3320 @ 2.50GHz
8Gb RAM
240GB SSD

Answer 1

We put a full-page cache WP-Rocket (paid) or WP Super Cache (free). We put on the Redis
server and a plugin for WordPress Redis Object Cache . We set up all this stuff and invite the admin to install nGinx, php7-fpm, MariaDB, Redis and tweak the web server settings.

Answer 2

oad average: 141.22, 140.41, 124.25

Check for viruses. Not so long ago there was a hole through which they were mining.

Answer 3

I would start with profiling.
If you are sure it is WP then install P3 (Plugin Performance Profiler) and run plugin audit.
Thus, it is possible to identify which plugins heavily load WP and which MySQL queries work for a long time.