The genoncfg Utility

Use the genoncfg utility to expedite the process of customizing the default Informix® configuration file (onconfig.std) to the host environment and your planned usage of a database server instance.


Read syntax diagramSkip visual syntax diagram
             |             '-informixdir-' |   
             +- -h-------------------------+   
             +- -V-------------------------+   
             '- -version-------------------'   

Element Purpose Key Considerations
input_file Name of the input file containing your parameter settings.  
informixdir Path to the Informix installation that you want to configure. You can omit the installation path if the INFORMIXDIR environment variable is set. If the INFORMIXDIR variable is already set and you enter an installation path on the command line, the utility runs with the command-line path.
-h Help information about the genoncfg utility.  
-V Displays short version information and exits the command-line utility.  
-version Displays extended version information and exits the command-line utility.  


Log in to the host computer as root or user informix before you run this utility.

You must set parameters that are valid for your host environment in an input file before you can successfully run the genoncfg utility. For all environments, the parameter disk is required in the input file. You can also enter directives in the input file. The directives are not required to run the utility, but they can be helpful in some circumstances.

The utility does not read or modify any existing configuration file. If you have a pre-existing ONCONFIG file in the host environment, none of its parameter values are changed when you run the utility. Therefore, you can review the recommended configuration settings before you put them in effect on a database server instance.

To use the genoncfg utility:
  1. Create the input file containing your values for the parameters that the genoncfg utility processes with a text editor.
  2. Run the utility with your input file. The configuration file (named onconfig) is generated and saved in the working directory.
  3. Optional: Rename the generated configuration file.
  4. If you want to run a database server instance with the generated configuration file, copy the file to $INFORMIXDIR/etc and update the ONCONFIG environment variable accordingly.

Input File for the genoncfg Utility

Use the input file to specify the following information about the database server instance:

  • number of anticipated online transaction processing (OLTP) connections
  • number of anticipated decision-support systems (DSS) connections
  • disk space
  • CPU utilization
  • network connection settings
  • recovery time
The input file is an ASCII text file. There is no required order for the parameters. The following is an example of an input file:
cpus 1
memory 1024 m
connection name demo_on onsoctcp 9088
servernum 1
oltp_connections 10
dss_connections 2
disk /opt/IBM/informix/demo/server/online_root 0 k 300 m
directive one_crit
directive debug
Table 1. Parameters of the Input File for the genoncfg Utility
Parameter Description
connection Server connection parameters:
  • name or alias, depending on whether the connection functions with a specific server name (the DBSERVERNAME parameter of the configuration file) or with an alternative server name (using the DBSERVERALIASES parameter of the configuration file)
  • name for the connection
  • type of server connection (equivalent to NETTYPE in the configuration file)
  • port number for the service

Example: connection name demo_on onsoctcp 9088

cpus Number of central processing units (CPUs) to allocate the instance. Example: cpus 1
directive Directives that can be used with the genoncfg utility.
  • one_crit: Configures the database server to store physical logs, logical logs, and data in the root dbspace only.
  • debug: Displays information in real time about the host environment and actions done on the configuration file.

Example: directive one_crit

This information can be helpful in troubleshooting problems with database server configuration. One scenario is that the debug directive can result in saving time. In this scenario, you read the displayed information and notice that the utility is creating an onconfig file that you do not want or that will not function. You stop the utility while it is still running, adjust the input file settings, and then rerun the utility with the modified input file.

disk Disk storage space settings for the instance:
  • location of the root dbspace
  • size of offset, in megabytes (m) or kilobytes (k)
  • size of root dbspace, in megabytes (m) or kilobytes (k)


UNIX: /opt/IBM/dbspace/rootdbs

Windows: d:\INFXDATA\rootdbs

Important: If you enter a path location that is the root dbspace of a working instance, the instance is overwritten and made unusable.
dss_connections Estimated number of decision-support systems (DSS) connections to the instance. For example, a query client or other application that obtains result sets for business intelligence can be a DSS connection. Example: dss_connections 2
memory Amount of memory, in megabytes (m), for the instance. Example: memory 1024 m
oltp_connections Estimated number of online transaction processing (OLTP) connections to the instance. Typically, an application that modifies the state of databases in the instance is an OLTP connection. Example: oltp_connections 10
rto_server_restart Specifies the amount of time, in seconds, that the database server has to recover from a problem after you restart Informix and bring it into online or quiescent mode. The value can be set either to 0 to disable the configuration parameter or to a value between 60 and 1800 to enable the parameter and indicate the number of seconds. Example: rto_server_restart 100 specifies the recovery time objective as 100 seconds.
servernum Unique ID of the database server instance. Example: servernum 1

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