LSPHP Options¶

LSPHP supports multiple configuration options, depending on the setup. Directives are used when configuring Apache configuration files, while environment variables are used specifically within LiteSpeed Web Server.

Directives¶

Use directives when using LiteSpeed Web Server with Apache configuration files. These directives can be used at either the Server or Virtual Host level.

<IfModule LiteSpeed>
...
</IfModule>

<IfModule LiteSpeed>
LSPHP_ProcessGroup on
LSPHP_Workers 15
</IfModule>

LSPHP_Workers¶

The LSPHP_Workers directive controls the maximum number of worker or child processes per account in a shared-hosting environment. This directive allows you to set higher concurrency for specific Virtual Hosts.

LSPHP_ProcessGroup¶

The LSPHP_ProcessGroup directive turns ProcessGroup mode on and off when using Apache configuration files. By default, this directive is set to on.

LSPHP_MaxWaitQ¶

The LSPHP_MaxWaitQ directive sets the maximum number of processes that can be in the PHP external application wait queue. When this limit is reached, new requests return a 508 “Resource Limit Reached” error. This is the same WaitQ that can be monitored in the WebAdmin Console under Actions > Real-Time Stats.

Variables¶

Use variables when settings must be configured globally in LiteSpeed Web Server. Set these variables in the WebAdmin Console. Navigate to Server > PHP > Environment.

For Apache-configuration-based servers, such as those using cPanel, Plesk, and DirectAdmin, set variable values in the Virtual Host's Apache configuration file:

<IfModule LiteSpeed>
LS_EXTAPP_ENV <variable_name>=<variable_value>
</IfModule>

<IfModule LiteSpeed>
LS_EXTAPP_ENV LSAPI_MAX_PROCESS_TIME=3600
</IfModule>

LSAPI_CHILDREN¶

Default Value: 35

PHP LSAPI supports a variety of process modes. Two of these modes, Worker and ProcessGroup, can be configured using this environment variable.

Setting LSAPI_CHILDREN to 1 puts LSWS in Worker mode. In Worker mode, LiteSpeed Web Server dynamically spawns new PHP processes as needed and kills them when they are no longer needed.

Setting LSAPI_CHILDREN to a number greater than 1 puts LSWS in ProcessGroup mode. In ProcessGroup mode, the web server starts one PHP parent process that runs continuously. This process then forks child PHP processes, rather than spawning new processes, as needed. The value set for LSAPI_CHILDREN controls the number of child processes that can be created.

ProcessGroup mode is generally preferred because all PHP processes can share one memory block for opcode caching.

LSAPI_AVOID_FORK¶

Default Value: 0

The LSAPI_AVOID_FORK environment variable specifies whether the internal process manager in ProcessGroup mode should try to avoid forking new child processes.

When set to 0, the internal process manager does not try to avoid forking new processes. To save system resources, it stops processes when they finish and starts child processes only when needed. This setting is often preferred in shared-hosting environments.

When set to 1, the internal process manager tries to avoid frequently stopping and starting child processes. This setting might be preferred in a dedicated-hosting environment because recycling existing processes may be faster, even if it sometimes results in unused processes remaining active.

LSAPI_EXTRA_CHILDREN¶

Default Values:

• If LSAPI_AVOID_FORK is set to 0: LSAPI_CHILDREN / 3
• If LSAPI_AVOID_FORK is set to 1: 0

In ProcessGroup mode, the LSAPI_EXTRA_CHILDREN environment variable controls the maximum number of extra child processes that can be started when existing child processes malfunction. The total number of child processes is reduced to the level set in LSAPI_CHILDREN as soon as service returns to normal.

LSAPI_MAX_REQS¶

Default Value: 10000

In ProcessGroup mode, this environment variable controls the number of requests each child process handles before exiting automatically. Several PHP functions have been identified as having memory leaks. This parameter can help reduce memory usage caused by leaky PHP functions.

LSAPI_MAX_IDLE¶

Default Value: 300 seconds

In ProcessGroup mode, LSAPI_MAX_IDLE controls how long an idle child process waits for a new request before exiting. This option helps release system resources used by idle processes.

LSAPI_MAX_IDLE_CHILDREN¶

Default Values:

• If LSAPI_AVOID_FORK is set to 0: LSAPI_CHILDREN / 3
• If LSAPI_AVOID_FORK is set to 1: LSAPI_CHILDREN

In ProcessGroup mode, LSAPI_MAX_IDLE_CHILDREN controls how many idle child processes are allowed. The parent process immediately kills extra idle child processes.

LSAPI_MAX_PROCESS_TIME¶

Default Value: 3600 seconds

The LSAPI_MAX_PROCESS_TIME environment variable controls the total time that a PHP process can spend processing a request. It is effective only in ProcessGroup or Daemon mode. The parent process kills child processes that exceed this threshold.

In ProcessGroup mode, LSAPI_MAX_PROCESS_TIME controls the maximum processing time allowed for a request. If a child process cannot finish processing a request within the specified time frame, the parent process kills it. This option can help remove dead or runaway child processes.

LSAPI_PGRP_MAX_IDLE¶

Default Value: FOREVER

In ProcessGroup mode, the LSAPI_PGRP_MAX_IDLE environment variable controls how long the parent process waits before exiting when no child processes are running. This option can help release system resources used by an idle parent process. This environment variable has the same function as the Max Idle Time setting in the WebAdmin Console under Configuration > External App > your_external_application.

LSAPI_PPID_NO_CHECK¶

Default Value: 0

By default, an LSAPI external application exits automatically when the parent process dies. This behavior reduces orphaned processes when the web server is restarted. However, disabling this feature may be desirable in certain situations, such as when an LSAPI process is started manually from the command line.

Adding the LSAPI_PPID_NO_CHECK environment variable and setting it to 1 disables the parent-process existence check. To turn this setting off, remove the environment variable completely. When PHP is started from the command line using the -b option, this check is disabled automatically.

LSAPI_ALLOW_CORE_DUMP¶

Default Value: 0

By default, an LSAPI application does not leave a core dump file when it crashes. To have LSPHP dump a core file, add this environment variable and set it to 1. When set to 1, core files are created in the current working directory, which is generally the directory of the PHP script that crashed. To turn off this setting, remove the environment variable completely.

LSAPI_ACCEPT_NOTIFY¶

Default Value: 0

By default, an LSAPI application sends a notification packet whenever it receives a request. Set this environment variable to 1 to notify the server only for newly established connections. This setting is recommended to improve LiteSpeed Web Server performance.

LSAPI_SLOW_REQ_MSECS¶

Default Value: 0

When set to a nonzero value, LiteSpeed Web Server logs requests to an error log file if a request takes longer than the specified number of milliseconds. This option can help identify scripts that are slowing down the server.

LSAPI_CLEAN_SHUTDOWN¶

Default Value:

• If PHP version is greater than 5.6: 1
• If PHP version is 5.6 or lower: 0

Available as of PHP LSAPI v7.6, the LSAPI_CLEAN_SHUTDOWN environment variable instructs LSPHP to automatically perform a clean shutdown. A clean shutdown performs cleanup after a PHP crash or abnormal exit, such as manually killing the process. Setting LSAPI_CLEAN_SHUTDOWN to 0 disables the clean-shutdown feature, while setting it to 1 enables it.

LS_OOM_SCORE_ADJ¶

As of LiteSpeed Web Server v6.0.12 build 2, the external application environment variable LS_OOM_SCORE_ADJ can apply oom_score_adj values to PHP processes independently of the value set for the parent LSWS process. The assigned value is applied to external applications started by the web server.

Use LS_OOM_SCORE_ADJ=<desired_value>, where <desired_value> is an integer in the -1000 to 1000 range. The lower the value, the lower the chance that the process is killed.

To illustrate why you might use this variable, consider a common scenario:

Your server has low free memory, and the OOM killer is invoked. You want to ensure that processes are sacrificed according to their importance, so you have set oom_score_adj accordingly. The problem is that setting oom_score_adj for the litespeed process also sets it for the process's children, including lsphp processes. While it is highly desirable to protect LiteSpeed Web Server from the OOM killer, it is also desirable for lsphp processes to be sacrificed to free memory.

In this scenario, use oom_score_adj to set the priority for the litespeed process as usual. In the WebAdmin Console, add the LS_OOM_SCORE_ADJ environment variable to the PHP tab. You may also add the variable to the configuration for an individual PHP application if it requires a different priority than PHP in general.

LSAPI_MAX_CMD_SCRIPT_PATH_LEN¶

When using top or ps to view PHP scripts run through LiteSpeed, the paths to the PHP scripts may be truncated at the beginning:

lsphp:ublic_html/example.com/wp-content/plugins/sample/plugin.php

The beginning of the full path is truncated, but you can configure LiteSpeed to display the full path:

/home/username/public_html/example.com/wp-content/plugins/sample/plugin.php

To display the full path, add LSAPI_MAX_CMD_SCRIPT_PATH_LEN=80 to the environment variables under the PHP tab or to your external applications, as applicable.

The maximum value is 255, and the default is 46.

Restart PHP to apply the change. Run the pkill lsphp command to do so.

LSAPI_STDERR_LOG¶

When PHP has standard error output, it normally uses the server-level stderr.log, which can be helpful for troubleshooting PHP-related issues, such as 503 errors.

You can enable and disable stderr.log in the WebAdmin Console using Configuration > Server Log > Server Log > Enable stderr Log.

To customize the log location, set LSAPI_STDERR_LOG relative to a user directory. For example, call a PHP script with the following content:

<?php
ini_set('error_log', '');
error_log("This test message to stderr, will go to LSWS error log!");

You should then see output similar to the following in the /var/log/apache2/error_log server log:

2025-11-07 07:07:56.568378 [NOTICE] [2677731] [T0] [192.0.2.10:56660:HTTP2-3#APVH_example.example.com:443] [STDERR] This test message to stderr, will go to LSWS error log!\n

You can also redirect output by using LSAPI_STDERR_LOG in the PHP environment.

In the WebAdmin Console, navigate to Configuration > PHP > PHP Handler Defaults > Environment and add the following:

<env>LSAPI_STDERR_LOG=/var/log/user/lsphp_stderr.log</env>

/var/log/user/ is a per-user mount through CloudLinux CageFS. The environment is set for all lsphp processes. When a user calls error_log() with an invalid file or directory configured, the output is written to that file instead of the LSWS server error log.

Alternatively, configure this at the Virtual Host level instead of at the PHP runtime level:

<IfModule LiteSpeed>
LS_EXTAPP_ENV LSAPI_STDERR_LOG=/path/to/your/vhost/stderr.log
</IfModule>

You may also want to use this configuration if stderr.log grows quickly and rapidly fills the disk with PHP warning messages:

PHP Warning: next() expects parameter 1 to be array, null given in /home/username/example.com/wp-includes/class-wp-hook.php on line 291
PHP Warning: current() expects parameter 1 to be array, null given in /home/username/example.com/wp-includes/class-wp-hook.php on line 275
PHP Warning: Invalid argument supplied for foreach() in /home/username/example.com/wp-includes/class-wp-hook.php on line 277
PHP Warning: next() expects parameter 1 to be array, null given in /home/username/example.com/wp-includes/class-wp-hook.php on line 291

The warnings may originate from different shared-hosting users, but all are logged to the main server stderr.log.

Excessive logging may occur because the PHP engine generates a large number of error and warning messages. To stop all stderr.log output, navigate to Configuration > Server Log > Server Log and set Enable stderr Log to No.

To stop only PHP-related error reporting in stderr.log, leave Enable stderr Log set to Yes, then add the following environment variable to the LSPHP external application configuration:

LSAPI_STDERR_LOG=/dev/null

This discards PHP-generated warning messages while still logging other errors.

LS_STDERR_LOG¶

LS_STDERR_LOG is similar to LSAPI_STDERR_LOG, but lscgid handles it before the external application process begins. As such, it applies to all types of external applications, such as Node.js, not only LSAPI applications.

LSPHP_ENABLE_USER_INI¶

To make .user.ini work with LSPHP, change the lsphpxx external application configuration by adding the following environment variable:

LSPHP_ENABLE_USER_INI=on

This directive has been supported since PHP LSAPI version v6.10.