Where does Bitrix log errors by default?

Three places: `/bitrix/php_interface/error_log` if `error_reporting` is set in dbconn.php; PHP's configured `error_log` directive (usually `/var/log/php_errors.log`); and the web server's error log (`/var/log/apache2/error.log` or `/var/log/nginx/error.log`). Bitrix module errors usually land in the first; PHP fatals in the second or third.

How do I turn on Bitrix's internal error log?

Edit `bitrix/php_interface/dbconn.php` and set `error_reporting(E_ALL ^ E_NOTICE ^ E_DEPRECATED ^ E_STRICT);` plus `ini_set('error_log', '/path/to/bitrix/php_interface/error_log');`. Don't enable `display_errors` on production — only log.

Bitrix log fills the disk — how to rotate?

Drop a logrotate config in `/etc/logrotate.d/bitrix`: `/var/www/*/bitrix/php_interface/error_log { daily; rotate 14; compress; missingok; notifempty; }`. Or move logging to syslog with `ini_set('error_log', 'syslog')` and let the OS handle rotation.

How do I tell if an error came from Bitrix core, a module, or PHP itself?

Bitrix core errors include the path `bitrix/modules/main/...`; third-party module errors include `bitrix/modules/./...`; raw PHP errors carry no Bitrix path. For PHP fatals that crash the page, check the web server error log first — Bitrix can't log a fatal that killed PHP before its handler ran.

Bitrix Error Log: How to Locate, Enable, and Analyze Logs

3 min read

11.08.2025

Error logs in Bitrix are essential for diagnosing issues such as server misconfigurations, PHP errors, or database-related problems. Understanding how to access and interpret these logs can help resolve issues faster.

Bitrix Error Log Locate Enable Analyze — Bitrix logs — sites/example/php_interface/error.log and dbconn.php.

For other Bitrix administration topics, see Setting mbstring.func_overload for Bitrix, Bitrix Virtual Appliance (BitrixVA), Fix "Memcache Extension is Not Loaded", and Bitrix MySQL Freezes — Causes and Solutions.

Locating the Bitrix Error Log

Bitrix-Specific Log Files

Bitrix has a built-in logging system. The logs can be found in:

/bitrix/php_interface/after_connect.php

/bitrix/modules/logs/

Web Server Log Files

Depending on your web server configuration:

Apache logs:

/var/log/apache2/error.log

Nginx logs:

/var/log/nginx/error.log

PHP-FPM logs:

/var/log/php7.x-fpm.log

Custom Error Log for Bitrix

If you have configured Bitrix to write custom logs, check the file path set in the code:

define("LOG_FILENAME", $_SERVER["DOCUMENT_ROOT"]."/bitrix/log.txt");

Log entries are saved in:

/bitrix/log.txt

Enabling Error Logging in Bitrix

Enable PHP Error Logging

Open your php.ini file:
```
sudo nano /etc/php/7.x/apache2/php.ini
```

Enable logging and set the log file:

log_errors = On

error_log = /var/log/php_errors.log

Restart the web server:
```
sudo systemctl restart apache2
```

Enable Bitrix Debugging

Edit the dbconn.php file in your Bitrix installation:

define("DEBUG_MODE", true); // Enable debugging

define("LOG_FILENAME", $_SERVER["DOCUMENT_ROOT"]."/bitrix/log.txt"); // Custom log file

Checking Common Errors in Bitrix Logs

Error Type	Typical Error	Fix
Database Connection Errors	`[DB Connection Error]: Unable to connect to the database`	Verify database credentials in dbconn.php. Check the MySQL service status: `sudo systemctl status mysql`
PHP Errors	`PHP Fatal error: Uncaught Error: Call to undefined function`	Ensure all required PHP modules are installed (e.g., php-mysql, php-gd). Install missing modules: `sudo apt install php-mysql php-gd`
Module Loading Errors	`Error: Unable to load module /bitrix/modules/some_module`	Check if the module directory exists. Reinstall the module if necessary.

Analyzing and Filtering Logs

Search for Specific Errors

Use grep to filter relevant log entries:

grep "ERROR" /bitrix/log.txt

Monitor Logs in Real-Time

Use tail to monitor logs as issues occur:

tail -f /bitrix/log.txt

Clearing Old Logs

Large log files can consume disk space and slow down the server.

Check the size of log files:

du -sh /bitrix/log.txt

Clear log files:

> /bitrix/log.txt

Best Practices for Bitrix Error Logging

Rotate Logs Automatically:

Use logrotate to manage large log files:

sudo nano /etc/logrotate.d/bitrix

Example configuration:

/var/www/bitrix/log.txt {

    daily

    rotate 7

    compress

    missingok

    notifempty

}

Set Appropriate Log Levels:
- Only enable detailed logging for troubleshooting.
- Disable detailed logs in production to improve performance.
Secure Log Files:
- Restrict permissions:

Locate and enable logs in /bitrix/log.txt or /var/log/.
Use error logs to debug database, PHP, or server-related issues.
Regularly clean and rotate logs to optimize performance.

Bitrix Error Log: How to Locate, Enable, and Analyze Logs

Locating the Bitrix Error Log

Bitrix-Specific Log Files

Web Server Log Files

Custom Error Log for Bitrix

Enabling Error Logging in Bitrix

Enable PHP Error Logging

Enable Bitrix Debugging

Checking Common Errors in Bitrix Logs

Analyzing and Filtering Logs

Search for Specific Errors

Monitor Logs in Real-Time

Clearing Old Logs

Best Practices for Bitrix Error Logging

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Bitrix Error Log: How to Locate, Enable, and Analyze Logs

Locating the Bitrix Error Log

Bitrix-Specific Log Files

Web Server Log Files

Custom Error Log for Bitrix

Enabling Error Logging in Bitrix

Enable PHP Error Logging

Enable Bitrix Debugging

Checking Common Errors in Bitrix Logs

Analyzing and Filtering Logs

Search for Specific Errors

Monitor Logs in Real-Time

Clearing Old Logs

Best Practices for Bitrix Error Logging

Hosting

Cloud Solutions

For You

VDS

Website Builders

Our services

Client Area

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