Follow-up: use ondemand PHP-FPM masters using systemd

A few days ago, I published a blogpost called A better way to run PHP-FPM. It's gotten a fair amount of attention. It detailed the use of the "ondemand" process manager as well as using a separate PHP-FPM master per pool, for a unique APC cache.

The setup works fine, but has the downside that you'll have multiple masters running -- an obvious consequence. Kim Ausloos created a solution for this by using systemd's socket activation. This means PHP-FPM masters are only started when needed and no longer stay active on the system when obsolete.

This has a few benefits and possible downsides;

  • Pro: masters are only spawned when needed, meaning less memory consumed overall
  • Pro: masters are also killed when they're obsolete, so a perfect ondemand scenario
  • Min: no longer able to restart a PHP-FPM pool when needed (to load new .INI settings), all pools would restart?
  • Min: APC cache will be destroyed whenever a PHP-FPM master is killed (which may not be a bad thing, for low-traffic sites)

I'll do some more testing on this use-case, as well as the performance penalty (if any) of having to start new master on a first request to the PHP-FPM socket. For this to work out, RHEL or CentOS 7 is needed in my case (we're a RHEL/CentOS shop), as systemd is required and will only be supported from RHEL/CentOS 7.

The Social Box

You can sign up for more updates via Twitter or Facebook below. On Twitter, I regularly talk about technology or tweet about interesting stories. Topics that don't necessarily make it to this blog. Facebook contains a steady update of blogposts and some more lightweight stories.

The @mattiasrss account has an automated RSS feed of all blogposts that get published.

Write a Comment

Do you care about the markup if your comment? You can use the following HTML tags:

<code>command</code>: command highlighting
<pre>text</pre>: pre-formatted code, can be multi-line (black background, white letters)

example <pre> tag
<blockquote>text</blockquote> quoted text
quoted example

None of this is needed of course, it's all optional!