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PHP, MySQL / MariaDB settings

iTop needs write access to the temp dir (this path is retrieved using the PHP function sys_get_temp_dir()). Check rights and also the openbase_dir PHP parameter !

PHP settings in php.ini

Recommended values in php.ini summary :

memory_limit = 256M ; could be increased if needed
max_input_vars = 5000
; upload_tmp_dir : should point to a directory with write access
; also check those options for attachments (se dedicated chapter below)
; adapt values depending of your preferences!
; - upload_max_filesize
; - max_file_uploads
; - post_max_size
; - max_input_time
If you're using CLI tools like cron.php, check also the PHP instance used for CLI !


On various use cases iTop send large amount of data to the server. Especially some XHR queries sends a description of the current object structure : list of attributes and all corresponding properties. If your datamodel adds lots of attributes on an object, you can get wrong behavior on one of those screens :

  • when editing objects with many relations (iTop creates one big form containing all the relations)
  • in a object list :
    • when ordering the list by clicking on a column header
    • after checking lots of attributes in the “configure this list” dialog

Such behavior can be caused by the webserver : the parameter max_input_vars in php.ini defines the maximum size of data sent to the server. Its default value is 1000, which might not be sufficient for such customized objects with many fields. If you get such behavior, you can update max_input_vars value from 1000 to 3000 or 5000 depending on the volume needed to be transferred.

This very same behavior may happen when Suhosin is installed. Refer to iTop and Suhosin for more information

Attchments upload

iTop is capable of uploading and storing documents (i.e files) as attachments to various objects (Tickets, CIs…). These documents are stored as binary blobs in the iTop database. In order to to safely upload and store documents, several settings must be adjusted consistently across PHP and MySQL.

In PHP, several variables govern the upload of files:

file_uploads Set to 1 to allow file upload, to zero to prevent all file uploads.
upload_tmp_dir The temporary location (on the server) were the uploaded files will be stored. Make sure that this parameter points to a location that is accessible (and writable) by the process running the web server (or by the end users in case of IIS with the Windows built-in authentication) and that there is enough space left.
upload_max_filesize The maximum size allowed for an uploaded file. The value is expressed in bytes. You can use units like K for kilobytes (=1024 bytes), M for megabytes and G for gigabytes. Example: 4M stands for 4 megabytes.
max_file_uploads The maximum number of files that can be uploaded simultaneously in a single web page. iTop should normally upload only one file at a time. You can safely use the default value, which is 20.
post_max_size The maximum amount of data that can be sent to the server via a POST request. This value MUST BE bigger than upload_max_filesize, since the same request will contain some more information (the title of the document, an operation code…). So it’s better to put a bigger value here. For example, if upload_max_filesize is 4M, then put 5M for post_max_size.
memory_limit After being uploaded on the server, the file will be read in memory before being stored in the database. Therefore make sure that memory_limit (if enabled) is far bigger than upload_max_filesize.
max_input_time This value defines the maximum time allowed for the server to read its input. This includes the time spent uploading the files. The default of 60 seconds may be exceeded for uploading big files over slow connections.
It is good practice to have the following relation between the various settings:
upload_max_filesize < post_max_size < max_allowed_packet < memory_limit
php.ini php.ini my.cnf php.ini

MySQL / MariaDB recommandations

innodb_buffer_pool_size = 512M
query_cache_size = 32M
query_cache_limit = 1M
innodb_default_row_format = DYNAMIC
innodb_large_prefix = true
; max_allowed_packet : should be set to a value bigger than upload_max_filesize in php.ini 
innodb_log_file_size must be at least 10 times bigger than max_allowed_packet
[ERROR] InnoDB: The total blob data length (35174918) is greater than 10% of the total redo log size (268435456). Please increase total redo log size.
If you ever have an issue linked with mysqldump, there is another parameter max_allowed_packet you can act on, in the same file my.cnf but under [mysqldump] section


As of iTop 2.5, the charset used is utf8mb4 with utf8mb4_general_ci collation. To allow iTop to correctly handle strings, the following requirements must be met :

  • MySQL version 5.5.3 or newer
  • innodb_default_row_format variable set to DYNAMIC (default value) or COMPRESSED
  • innodb_large_prefix set to true


The uploaded files are stored into the MySQL database, each file in one query. Therefore the maximum size allowed for a query MUST BE BIGGER than the maximum size of the uploaded file. This is configured via the variable max_allowed_packet in the my.cnf configuration file (on the MySQL server).

2_7_0/install/php_and_mysql_configuration.txt · Last modified: 2021/05/11 09:28 (external edit)
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