Question Website becomes very slow on 500 pps

[MaxChri]

Server operating system version

Debian 11

Plesk version and microupdate number

18.0.43

Hey!

I want to setup a plesk server which should handle at least 10.000 pps. The web application itself is light weight and really fast. Images will be cached by a cdn, so the server should only process the requests and minor mysql queries.

I have a test server with 4 cpu and 8 GB RAM. This server will not be used for the 10k project but I have tested this server with just 500 pps
and the web application (dedicated fpm served by apache) got really slow. The response time for this small amount of requests is up to 7 seconds.

I have not increased the apache2 workers or anything else. But in the monitoring I found out, that the apache, nginx and mysql service response times increased a lot.
In this case I want to ask, does it even matter if I increase the workers (fine tuning) or would the response time of the services increase so much that the webserver could not handle more than a certain amount of requests? My goal was 10k but I'm curious if it even works, when I get a dedicated live server with lots of resources.

Would appreciate some feedback from you.

https://imgur.com/7sXBpPq

 

[weltonw]

Needs more information (was CPU saturated? RAM?)...load testing + monitoring worker status may help.

You may want to try raising Apache worker limits though.

 

[MaxChri]

Needs more information (was CPU saturated? RAM?)...load testing + monitoring worker status may help.

You may want to try raising Apache worker limits though.

CPU and RAM didn't changed much, the server had enough resources left. I have stress tested it with a custom tool which simulates lots of http requests. In this case around 250 http requests per second.

Does the apache response delay reduce if I just increase the worker limits? And as far as I can see, nginx and mysql also have a significant peak. Let's say the requests would increase 10x more. Would a good plesk server handle this or would the requests cause overflowing the technical limits?