Question

Slow page load with PHP-FPM 7.2

Posted January 19, 2021 2k views
ApachePHPPHP Frameworks

Hi guys,

i’m having troubles with PHP-FPM.

My droplet:

Dedicated 8 vCPUs
32 GB RAM
Ubuntu 18.04.3 (LTS) x64

RAM usage - about 10%
CPU usage - about 6%

My application has about 600 online users (on the top usage time). The avarage proccess memory is about 90mB.

My PHP-FPM pool config:

pm = dynamic
pm.maxchildren = 300
pm.start
servers = 32
pm.minspareservers = 16
pm.maxspareservers = 32
pm.processidletimeout = 5s
pm.max_requests = 1000

process.max = 512 (php-fpm.config)

The problem:

At random times, my application stay very very slow, almost frozed. My log said:

[18-Jan-2021 17:31:26] WARNING: [pool www] seems busy (you may need to increase pm.startservers, or pm.min/maxspare_servers), spawning 16 children, there are 178 idle, and 256 total children

Then, i increase drastically (3x more) (maxchildren, startservers, min/maxspareservers and max_requests), and restartáramos php7.2-fpm service. And then, no changes happen.

So, i return to original parameters (with 20% more then initial) and no effects.

And after 40/50min of slowing, my system returns to normal velocity. And I dont know what causes this.

Does someone can help me?

Thnks since now!

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2 answers

Hi @vbrodrigo,

You’ve added the setting pm.maxchildren = 300 however you need to check if your Apache workers and make sure there are at least 300 available.

Basically, the Apache workers are equivalent to a room full of seats. These seats are the projection to your website. When someone opens your website, it’s like one person going to this room and sitting on one of the chairs. When the limit is reached, in order for a person to load your website, another one needs to close it. So basically, I’ll suggest increasing that value as well.

Another thing I would recommend is using pm = static. I remember I had some issues with dynamic previously. Try it out and let me know how it goes please.

Regards,
KFSys

Hello,

I’m just posting the typical issues/resolutions to such cases. They are almost every time connected with two things - Website Optimization and Server/Droplet Optimization.

Let’s start with Server Optimization.

When looking at Server/Droplet Optimization, there are a few necessary services/packages that are universal.

  • The first one would be Server-side caching. Server cache is an umbrella term covering a number of different types of caching. This includes Content Delivery Network (CDN) caching, object caching, and opcode caching. Depending on what you want to achieve you might need one or the other. Usually, though, you can have all 3 types of caching as it shouldn’t interfere with your Website/App. I won’t go into more details about what each caching does as this post will become 3 pages long. There are multiple documents providing services/packages for each of the server-type caching.

  • Next would be using PHP-FPM (if your Website is using PHP of course). PHP-FPM is an efficient method on how to minimize the memory consumption and rise the performance for the Websites with heavy traffic. It is significantly faster than traditional CGI-based methods in multi-user PHP environments.

  • Another solution would be Database Caching. A database cache supplements your primary database by removing unnecessary pressure on it, typically in the form of frequently accessed read data. The cache itself can live in a number of areas including your database, application or as a standalone layer. Usually, for this kind of caching is being used Redis.

  • Apache NPM modules. If you are using Apache, you are using one of three NPM modules. Most certainly if you haven’t configured anything on it and have used the default configuration, you are using NPMPrefrok which is the most outdated one and thus the slower. I’ll recommend using one of the other two - NPMWorker and NPM_Event depending on your situation. Again, I would urge you to read more about these 3 and what is applied in which case.

  • Apache Workers. Basically, the Apache workers are equivalent to a room full of seats. These seats are the projection to your website. When someone opens your website, it’s like one person going to this room and sitting on one of the chairs. When the limit is reached, in order for a person to load your website, another one needs to close it. So basically, I’ll suggest increasing that value as well.

Those were the basic optimizations on a server level, let’s start with your Website/App

If you are using a CMS like WordPress, Magento, Joomla, Opencart or anything of the same matter, there will be plugins/addons. These addons can be very powerful if used correctly. The most helpful plugins are:

  • Caching Plugins
  • Image Optimization Plugins
  • Plugins that reduce redirections/requests
  • Plugins that reduce the size of JS and CSS files.
  • More often than not, there are a lot of JS and CSS files that are not being used, removing those should work as well

If you are not using a CMS, you’ll need to try and do what these plugins are doing manually.

Usually, Websites/Apps are slow because of a couple of reasons which range from too many requests or big images to a bunch of unnecessarily big JS or CSS files. Optimizing these whether you are using a Plugin or doing it manually is enough.

I hope this was helpful.

Regards,
KFSys