Process Configuration File

The database server uses configuration parameters to allocate shared-memory segments during initialization. If you change the size of shared memory by modifying a configuration-file parameter, you must take the database server to offline mode and then reinitialize shared memory.

During initialization, the database server looks for configuration values in the following files, in this order:

1. If the ONCONFIG environment variable is set, the database server reads values from the $INFORMIXDIR/etc/$ONCONFIG file.

   If the ONCONFIG environment variable is set, but the database server cannot access the specified file, it returns an error message.

2. If the ONCONFIG environment variable is not set, the database server reads the configuration values from the $INFORMIXDIR/etc/onconfig file.
3. If you omit a configuration parameter in your onconfig file, the database server reads the configuration values from the $INFORMIXDIR/etc/onconfig.std file.

It is recommended that you always set the ONCONFIG environment variable before you initialize the database server. The default configuration files are intended as templates and not as functional configurations. For more information about the configuration file, refer to Preparing the ONCONFIG Configuration File.

The initialization process compares the values in the current configuration file with the previous values, if any, that are stored in the root dbspace reserved page, PAGE_CONFIG. For more information about PAGE_CONFIG, refer to the chapter on configuration parameters in the IBM Informix: Administrator's Reference. When differences exist, the database server uses the values from the current ONCONFIG configuration file for initialization.