FPM uses php.ini syntax for its configuration file - php-fpm.conf, and pool configuration files.

List of global php-fpm.conf directives

pid string

Path to PID file. Default value: none.

error_log string

Path to error log file. Default value: #INSTALL_PREFIX#/log/php-fpm.log. If it's set to "syslog", log is sent to syslogd instead of being written in a local file.

log_level string

Error log level. Possible values: alert, error, warning, notice, debug. Default value: notice.

syslog.facility string

used to specify what type of program is logging the message. Default value: daemon.

syslog.ident string

Prepended to every message. If you have multiple FPM instances running on the same server, you can change the default value which must suit common needs. Default value: php-fpm.

emergency_restart_threshold int

If this number of child processes exit with SIGSEGV or SIGBUS within the time interval set by emergency_restart_interval, then FPM will restart. A value of 0 means 'Off'. Default value: 0 (Off).

emergency_restart_interval mixed

Interval of time used by emergency_restart_interval to determine when a graceful restart will be initiated. This can be useful to work around accidental corruptions in an accelerator's shared memory. Available Units: s(econds), m(inutes), h(ours), or d(ays). Default Unit: seconds. Default value: 0 (Off).

process_control_timeout mixed

Time limit for child processes to wait for a reaction on signals from master. Available units: s(econds), m(inutes), h(ours), or d(ays) Default Unit: seconds. Default value: 0.

process.max int

The maximum number of processes FPM will fork. This has been design to control the global number of processes when using dynamic PM within a lot of pools. Use it with caution. Default value: 0.

process.priority int

Specify the nice(2) priority to apply to the master process (only if set). The value can vary from -19 (highest priority) to 20 (lower priority). Default value: not set.

daemonize boolean

Send FPM to background. Set to 'no' to keep FPM in foreground for debugging. Default value: yes.

rlimit_files int

Set open file descriptor rlimit for the master process. Default value: Set open file descriptor rlimit for the master process.

rlimit_core int

Set max core size rlimit for the master process. Default value: 0.

events.mechanism string

Specify the event mechanism FPM will use. The following is available: select, pool, epoll, kqueue (*BSD), port (Solaris). Default value: not set (auto detection).

systemd_interval int

When FPM is build with systemd integration, specify the interval, in second, between health report notification to systemd. Set to 0 to disable. Default value: 10.

List of pool directives

With FPM you can run several pools of processes with different setting. These are settings that can be tweaked per pool.

listen string

The address on which to accept FastCGI requests. Valid syntaxes are: '', 'port', '/path/to/unix/socket'. This option is mandatory for each pool.

listen.backlog int

Set listen(2) backlog. A value of '-1' means unlimited. Default value: -1.

listen.allowed_clients string

List of IPv4 addresses of FastCGI clients which are allowed to connect. Equivalent to the FCGI_WEB_SERVER_ADDRS environment variable in the original PHP FastCGI (5.2.2+). Makes sense only with a tcp listening socket. Each address must be separated by a comma. If this value is left blank, connections will be accepted from any ip address. Default value: any. IPv6 addresses are allowed since PHP 5.5.20 and 5.6.4.

listen.owner string

Set permissions for unix socket, if one is used. In Linux, read/write permissions must be set in order to allow connections from a web server. Many BSD-derived systems allow connections regardless of permissions. Default values: user and group are set as the running user, mode is set to 0660. string

See listen.owner.

listen.mode string

See listen.owner.

listen.acl_users string

When POSIX Access Control Lists are supported you can set them using this option. When set, listen.owner and are ignored. Value is a comma separated list of user names. Since PHP 5.6.5.

listen.acl_groups string

See listen.acl_users. Value is a comma separated list of group names. Since PHP 5.6.5.

user string

Unix user of FPM processes. This option is mandatory.

group string

Unix group of FPM processes. If not set, the default user's group is used.

pm string

Choose how the process manager will control the number of child processes. Possible values: static, ondemand, dynamic. This option is mandatory.

static - the number of child processes is fixed (pm.max_children).

ondemand - the processes spawn on demand (when requested, as opposed to dynamic, where pm.start_servers are started when the service is started.

dynamic - the number of child processes is set dynamically based on the following directives: pm.max_children, pm.start_servers, pm.min_spare_servers, pm.max_spare_servers.

pm.max_children int

The number of child processes to be created when pm is set to static and the maximum number of child processes to be created when pm is set to dynamic. This option is mandatory.

This option sets the limit on the number of simultaneous requests that will be served. Equivalent to the ApacheMaxClients directive with mpm_prefork and to the PHP_FCGI_CHILDREN environment variable in the original PHP FastCGI.

pm.start_servers int

The number of child processes created on startup. Used only when pm is set to dynamic. Default Value: min_spare_servers + (max_spare_servers - min_spare_servers) / 2.

pm.min_spare_servers int

The desired minimum number of idle server processes. Used only when pm is set to dynamic. Also mandatory in this case.

pm.max_spare_servers int

The desired maximum number of idle server processes. Used only when pm is set to dynamic. Also mandatory in this case.

pm.max_requests int

The number of requests each child process should execute before respawning. This can be useful to work around memory leaks in 3rd party libraries. For endless request processing specify '0'. Equivalent to PHP_FCGI_MAX_REQUESTS. Default value: 0.

pm.status_path string

The URI to view the FPM status page. If this value is not set, no URI will be recognized as a status page. Default value: none.

ping.path string

The ping URI to call the monitoring page of FPM. If this value is not set, no URI will be recognized as a ping page. This could be used to test from outside that FPM is alive and responding. Please note that the value must start with a leading slash (/).

ping.response string

This directive may be used to customize the response to a ping request. The response is formatted as text/plain with a 200 response code. Default value: pong.

request_terminate_timeout mixed

The timeout for serving a single request after which the worker process will be killed. This option should be used when the 'max_execution_time' ini option does not stop script execution for some reason. A value of '0' means 'Off'. Available units: s(econds)(default), m(inutes), h(ours), or d(ays). Default value: 0.

request_slowlog_timeout mixed

The timeout for serving a single request after which a PHP backtrace will be dumped to the 'slowlog' file. A value of '0' means 'Off'. Available units: s(econds)(default), m(inutes), h(ours), or d(ays). Default value: 0.

slowlog string

The log file for slow requests. Default value: #INSTALL_PREFIX#/log/php-fpm.log.slow.

rlimit_files int

Set open file descriptor rlimit for child processes in this pool. Default value: system defined value.

rlimit_core int

Set max core size rlimit for child processes in this pool. Possible Values: 'unlimited' or an integer greater or equal to 0. Default value: system defined value.

chroot string

Chroot to this directory at the start. This value must be defined as an absolute path. When this value is not set, chroot is not used.

chdir string

Chdir to this directory at the start. This value must be an absolute path. Default value: current directory or / when chroot.

catch_workers_output boolean

Redirect worker stdout and stderr into main error log. If not set, stdout and stderr will be redirected to /dev/null according to FastCGI specs. Default value: no.

clear_env boolean

Clear environment in FPM workers. Prevents arbitrary environment variables from reaching FPM worker processes by clearing the environment in workers before env vars specified in this pool configuration are added. Since PHP 5.4.27, 5.5.11, and 5.6.0. Default value: Yes.

security.limit_extensions string

Limits the extensions of the main script FPM will allow to parse. This can prevent configuration mistakes on the web server side. You should only limit FPM to .php extensions to prevent malicious users to use other extensions to execute php code. Default value: .php.

It's possible to pass additional environment variables and update PHP settings of a certain pool. To do this, you need to add the following options to the pool configuration file.

Example #1 Passing environment variables and PHP settings to a pool

env[PATH] = /usr/local/bin:/usr/bin:/bin
env[TMP] = /tmp
env[TMPDIR] = /tmp
env[TEMP] = /tmp

php_admin_value[sendmail_path] = /usr/sbin/sendmail -t -i -f
php_flag[display_errors] = off
php_admin_value[error_log] = /var/log/fpm-php.www.log
php_admin_flag[log_errors] = on
php_admin_value[memory_limit] = 32M
PHP settings passed with php_value or php_flag will overwrite their previous value. Please note that defining disable_functions or disable_classes will not overwrite previously defined php.ini values, but will append the new value instead.

Settings defined with php_admin_value and php_admin_flag cannot be overriden with ini_set().

As of 5.3.3, PHP settings are also possible to be set in webserver.

Example #2 set PHP settings in nginx.conf

set $php_value "pcre.backtrack_limit=424242";
set $php_value "$php_value \n pcre.recursion_limit=99999";
fastcgi_param  PHP_VALUE $php_value;

fastcgi_param  PHP_ADMIN_VALUE "open_basedir=/var/www/htdocs";

Because these settings are passed to php-fpm as fastcgi headers, php-fpm should not be bound to a worldwide accessible address. Otherwise, anyone could alter the PHP configuration options. See also listen.allowed_clients.

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User Contributed Notes 10 notes

4 years ago
It seems there is no way to get informed about the access log format codes that are used or can be used. All I found is the source code.

It would really help, not to have open questions when deploying php-fpm. I constantly struggle with file paths for example, but that is another topic.

                                case '%': /* '%' */
                                case 'C': /* %CPU */
                                case 'd': /* duration µs */
                                case 'e': /* fastcgi env  */
                                case 'f': /* script */
                                case 'l': /* content length */
                                case 'm': /* method */
                                case 'M': /* memory */
                                case 'n': /* pool name */
                                case 'o': /* header output  */
                                case 'p': /* PID */
                                case 'P': /* PID */
                                case 'q': /* query_string */
                                case 'Q': /* '?' */
                                case 'r': /* request URI */
                                case 'R': /* remote IP address */
                                case 's': /* status */
                                case 'T':
                                case 't': /* time */
                                case 'u': /* remote user */
gadnet at aqueos dot com
8 years ago
the doc is lacking a lot of things it seems.

  The php fpm exemple config file indicate different thing, more option etc... I wonder why the main documentation is less verbose that the configuration file that user can have .. or not have ?
frederic at juliana-multimedia dot com
3 years ago
With Apache, mod_proxy_fcgi and php-fpm, if you want to have a generic pool and several vhost with different php configuration, you can use the ProxyFCGISetEnvIf directive and the PHP_ADMIN_VALUE environment variable. It does not work with PHP_ADMIN_FLAG even for boolean directives.

PHP directives must be separated by spaces and a \n.

ProxyFCGISetEnvIf "true" PHP_ADMIN_VALUE "open_basedir=/var/www/toto/:/tmp/ \n session.save_path=/var/www/toto/session \n display_errors=On \n error_reporting=-1"
11 years ago
The default value for listen.backlog isn't exactly "unlimited".

It's 128 on some operating systems, and -1 (which doesn't mean "unlimited" as well, but is an alias to a hard limit) on other systems.

Check for a sysctl value like kern.somaxconn (OpenBSD) or net.core.somaxconn (Linux).

Crank it up if you need more PHP workers than the default value. Then adjust listen.backlog in your php-fpm configuration file to the same value.

rob at librobert dot net
1 year ago
Correction for my previous note...

I wrote "The 'index' directive that is used in php-fpm.conf".

But obviously I meant "The 'include' directive"...
rob at librobert dot net
1 year ago
The 'index' directive that is used in php-fpm.conf is not documented here. However, this directive can also be used in the pool configurations. In the included file, the $pool variable is substituted correctly.

This means that, if you have multiple pools with similar configurations, you can create a file '' like so:

listen.allowed_clients =

pm = dynamic
pm.max_children = X
pm.min_spare_servers = X
pm.max_spare_servers = X

access.log = /var/log/php-fpm/$pool.access
access.format = "%R %u [%t] \"%m %r\" %s %d %l"
slowlog = /var/log/php-fpm/$pool.slow

php_flag[short_open_tag] = off

And then include that file in each pool configuration like so:

user = www-vhost1
group = www-vhost1

listen =

include = /usr/local/etc/php-fpm.d/

This makes things a bit more transparent, and it could potentially save some time if you decide to change settings.

Make sure the name of the included file does not end in '.conf', because all files with that extension are loaded from php-fpm.conf.
david dot cancalon at proxeem dot fr
1 year ago
Be very carrefull when using ProxyFCGISetEnvIf within a Apache virtual host configuration using a shared PHP-FPM pool. Values defined like this are shared across all the Apache virtual hosts within a pool worker, may resulting in strange behaviours depending on the requests chronology.

See full explanation here:
Yousef Ismaeil Cliprz
8 years ago
Check if fastCGI enabled

// You can use isset or is_null for $_SERVER['FCGI_SERVER_VERSION']
function isFastCGI () {
    return !

sroussey at gmail dot com
9 years ago
Starting in 5.3.9 the security.limit_extensions configuration item has been added and it defaults to .php. If you need to execute other extensions, you have to change this setting.
7 years ago
If you need to disable security.limit_extensions variable, simply set the variable to FALSE like so:

security.limit_extensions = FALSE
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