When working with PHP, one of the most important files you'll encounter is the php.ini file. This configuration file controls nearly every aspect of how PHP behaves on your server - from error logging to file uploads, session handling, performance tweaks, and security settings.

- What is php.ini?

  • php.ini is the main configuration file for PHP.
  • It defines environment options, extensions, and behaviors for PHP applications.
  • It is loaded when the PHP engine starts (e.g., Apache + mod_php, PHP-FPM, CLI).

Depending on your environment, there may be multiple php.ini files.

Sections in php.ini

Although php.ini is a flat configuration file, its directives are logically grouped into sections for readability. Some of the main sections include:

  • [PHP] - General PHP configuration.
  • [Date] - Default timezone and date settings.
  • [intl] - Internationalization functions.
  • [Session] - PHP session handling.
  • [Assertion] - Runtime assertion options.
  • [mbstring] - Multibyte string handling.
  • [curl] - cURL extension.
  • [openssl] - OpenSSL encryption.
  • [opcache] - PHP opcode caching and optimization.

General PHP Settings

engine=On

Enables or disables the PHP engine.

short_open_tag=Off

Allows the use of <? ?> instead of <?php ?>.

precision=14

Sets the number of significant digits in floating-point numbers.

output_buffering=4096

Controls output buffering.

zlib.output_compression=Off

Enables transparent output compression.

Error Handling & Logging

display_errors=Off

Show errors in the browser.

log_errors=On

Save errors to log files.

error_log=php_errors.log

Path to error log file.

error_reporting=E_ALL & ~E_DEPRECATED & ~E_STRICT

Defines the error levels to report.

track_errors=Off

Store the last error in $php_errormsg.

File Uploads & POST Handling

file_uploads=On

Enables HTTP file uploads.

upload_max_filesize=10M

Maximum size of uploaded files.

max_file_uploads=10

Maximum number of files allowed in one request.

post_max_size=20M

Maximum size of POST data (affects file uploads too).

Resource Limits

memory_limit=128M

Maximum memory per script.

max_execution_time=30

Maximum execution time (seconds).

max_input_time=60

Time allowed for input parsing.

max_input_vars=1000

Limits number of input variables.

Session Handling

session.save_handler=files

Session storage method (files, memcached, redis).

session.save_path="/var/lib/php/sessions"

Path to session files.

session.gc_maxlifetime=1440

Lifetime of session data in seconds.

session.cookie_lifetime=0

Lifetime of session cookies.

session.cookie_secure=On

Sends cookies only over HTTPS.

Date & Time

date.timezone="UTC"

Defines default timezone.

Security & Restrictions

allow_url_fopen=Off

Allows accessing files via URL.

allow_url_include=Off

Allows include/require with URL.

disable_functions=exec,passthru,shell_exec,system

Disables dangerous functions.

disable_classes=mysqli,socket,SoapServer

Disables specified classes.

expose_php=Off

Whether PHP exposes its version in headers.

Performance & Caching

realpath_cache_size=4096k

Sets size of realpath cache.

opcache.enable=1

Enables OPcache for performance.

opcache.memory_consumption=128

Amount of memory for OPcache.

opcache.max_accelerated_files=10000

Maximum cached files.

Source: Orkhan Alishov's notes