how to benchmark server performance

[Stifmeister]

How can i benchmark my website in realistic load times for users?

Couple of months ago, I bought dedicated server, installed LEMP + redis, configured page/object cache, used perfmatters plugin to get rid of WP clutter and it looked really good.

Recently the site slowed down, as it has decent traffic, I disabled all caching plugins and redis, now my site runs like a dream.

The whole problem I have is that my dedicated server is max on 12% cpu usage, 8gb ram used out of 128gb. How can I even utilize the entire server? Is basic LEMP stack enough?

Is there perhaps some tool out there where I can rebuild my website on a new domain just for testing purposes and stress test/benchmark its performance, because now I'm just blindly doing "optimizations" on a live-site that impacts my end users and it's never an accurate result as maybe it was a spike in users or it's just a downturn, it's too random to try with real users.

Any suggestions?

 

[coollady123]

You may be hitting some other bottlenecks. (other than CPU/memory).

Since its a LEMP stack, I'm guessing your apps are using PHP.

I'm guessing it has hit PHP limits.

Try searching for "How to increase PHP limits" in Google.

 

[Entexion]

I can take a look at it for you free of charge, if you wish. Let me know. Systems admin with over 20 years of experience.

 

[Stifmeister]

You may be hitting some other bottlenecks. (other than CPU/memory).

Since its a LEMP stack, I'm guessing your apps are using PHP.

I'm guessing it has hit PHP limits.

Try searching for "How to increase PHP limits" in Google.

do you perhaps know of any tools or services that can accurately benchmark my server?

I would make changes and then benchmark again, this would yield actual scientific results as to whats the issue

 

[Stifmeister]

You may be hitting some other bottlenecks. (other than CPU/memory).

Since its a LEMP stack, I'm guessing your apps are using PHP.

I'm guessing it has hit PHP limits.

Try searching for "How to increase PHP limits" in Google.

also in my config the setting is on;
memory_limit = -1

 

[DozeX]

Don't build websites with wordpress, problem solved.

 

[Stifmeister]

Don't build websites with wordpress, problem solved.

What would someone who doesn't know how to code use?

 

[stromind]

Been there. Optimized everything—LEMP, Redis, caching, stripping WP bloat—looked great initially. But when traffic picked up, things slowed down. Disabled Redis & caching, and boom, the site runs smoother than ever.


Your issue sounds similar: your server isn't maxing out, but site performance suffers. Basic LEMP is solid, but there’s more to it. Instead of tweaking live, set up a staging site (clone your site on a subdomain).


Load Testing – k6, Loader.io, JMeter → simulate real traffic & stress test.
Performance Tools – GTmetrix, WebPageTest, PageSpeed Insights → detailed insights.
Find Bottlenecks – Slow MySQL queries? PHP worker limits? Disk I/O? Network latency?
Caching Strategy – Redis can help or hurt; try Nginx FastCGI cache for full-page caching.


You’re likely hitting an application-level bottleneck, not a hardware limit. Benchmark first, then optimize smart.