VDS cannot withstand the load. What to do?

Question

Highload

Good afternoon.
We had two sites (one on WP), the second on the QPL Board engine. Worked on shared hosting. Everything was fine. We decided to transfer to VDS. We took XEON 2, 10 gigs of RAM. Transferred the site to WP - there were problems, set up the server, installed varnish, memcache, nginx + phpfm. Everything works well.
We put the second site, now the server can not stand it. It is necessary to configure the server and under it. Probably give part of the load to the RAM instead of the processor.
Attendance of the first site is 4000 per day (www.fara.tj), and the second is 5000 (www.somon.tj). This is the maximum so far.
We are waiting for suggestions.

Answer 1

What to do?

Change maintenance administrator/programmer.

Answer 2

And I think all your problems are because of WordPress

Answer 3

There are two ways:
1. Take a separate VPS / VDS for the second site and add resources to the site that needs it
2. Hire a programmer to optimize sites

Answer 4

4000 per day is about 5*4000 / 24 / 60 / 60 = 0.2 requests per second. That is, 1 request in 4 seconds puts your VDS on a heon with 10 gigs of RAM?)

Answer 5

4k a day what? Requests / competitive connections / ... And just 4k is about nothing.
Start by determining what is eating up your resources. Use XHProf to identify performance bottlenecks and rewrite them. The main execution time, as a rule, is the database, the absence or not optimal caching, requests to external servers.

Answer 6

You took the norms of iron, but I'm afraid you didn't set it up.
Make tuning the web server, php, database, sessions, cache, etc.
Then everything will take off.

Answer 7

As an option - rent or buy servers that exceed the current configuration in terms of characteristics. Or do some optimization. Intensive and extensive ways, so to speak.

Answer 8

It is customary to answer such "questions" by looking at the server console from the root.
Most likely, you have OpenVZ (then you can try to blame it on KVM with an SSD), or a million plugins are screwed to WP, which in total slow down, or you yourself have already overdone the settings, making it worse than default.
Or maybe WP still goes to a remote database. There can be many reasons.
And according to the available data, only a telepath with a level a couple of orders higher than us gathered here will answer.