I set up my nginx with php-fpm. each vhost has its own unix-socket and separate POOL.
But the problem is that php-fpm is creating 7 thread for each config pool that I created in /etc/php5/fpm/pool.d/

why? and how could I define that the pool creates only when the url related to VHOST is viewed.

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  • Out of curiosity: what program does that screenshot come from? It looks like top, except for the line drawing and visual meters at the top. – MvG Dec 20 '13 at 9:03
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    @MvG it is htop and this screenshot is taken by android device connecting to server with juicessh by MOSH protocol. – r004 Jan 26 '14 at 15:23

The number of children is controlled by the process manager configuration directives in the pool configuration file. I guess the current settings are either pm = static with pm.max_children = 6 or pm = dynamic with pm.start_servers = 6. One process would be the controlling process, the others would be children ready to handle requests. If you only have 5 not 6 children configured, then I must confess I don't know what that last process is used for. On large high-throughput sites, such a configuration with many ready-to-use children makes sense, but in a memory-constrained (probably virtual) environment where you only expects PHP scripts to execute every now and then, a different configuration might be more appropriate.

To achieve this, edit the pool config files and set pm = ondemand. Then children will be created only to handle requests. This will mean less memory consumption while no requests are active, although it might also mean more time required to create a child. The latter can be reduced by choosing a reasonable pm.process_idle_timeout, so that a sane number of php processes remain idle while users can be expected to use them again soon. That “sane number” is controlled by pm.max_children.

Note: This advice is based on my experience with Debian 7, but it should apply to Ubuntu as well.

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  • Thanks MvG; there is two side to this problem here; firt why 7 processes for each VHOST.conf file that reside in /etc/php5/fpm/pool.d/. clearly there is something wrong? yes? and the second part of my Q? that you answered rather nicely. – r004 Dec 19 '13 at 17:44
  • @r004: I tried to shed more light on what's happening here, but there is more guesswork involved there: I understand the cure better than the problem. – MvG Dec 19 '13 at 18:06
  • No, I got what yo were trying to explain. Now with these directives or switches in php-fpm; a door way got open for me; to take control of my PHP environment. Now i am trying to findout more about these directive related to php-fpm. – r004 Dec 19 '13 at 19:55
  • all these directive is being set in /etc/php5/fpm/php-fpm.conf? – r004 Dec 19 '13 at 19:57
  • So between less memory and more time to process the request is it sane to set an static pool but with fewer children especially in a VPS environment? – r004 Dec 19 '13 at 20:01

Lots of people encourage to use pm=ondemand to save memory. However, it also means that your time to first byte (or server answer ) is going to be very big because if your web server had no recent visits, the php-fpm module will have to first create a child before answering a request. If you use pm=dynamic, it means you will always have at least 1 child ready to answer a client request. The following will load 1 child per user after restarting php-fpm

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