Configuring for recovery of restore point data in case an upgrade fails

By default, the CONVERSION_GUARD configuration parameter is enabled and a temporary directory is specified in the RESTORE_POINT_DIR configuration parameter. These configuration parameters specify information that Informix® can use if an upgrade fails. You can change the default values of these configuration parameters before beginning an upgrade.

Before you begin

Prerequisites: The directory specified in the RESTORE_POINT_DIR configuration parameter must be empty before the upgrade begins, but not when recovering from a failed update.

Important:

After a failed upgrade, do not empty the RESTORE_POINT_DIR directory before you attempt to run the onrestorept utility. The server must be offline after a failed upgrade.

About this task

You can change the value of the CONVERSION_GUARD configuration parameter or the directory for restore point files before beginning an upgrade. The default value for the CONVERSION_GUARD configuration parameter in the ONCONFIG file is (2), and the default directory where the server will store the restore point data is $INFORMIXDIR/tmp. You must change this information before beginning an upgrade. You cannot change it during an upgrade.

Procedure

To change information:

  1. If necessary for your environment, change the value of the CONVERSION_GUARD configuration parameter.

    When the CONVERSION_GUARD configuration parameter is set to 2 (the default value), the server will continue the upgrade even if an error related to capturing restore point data occurs, for example, because the server has insufficient space to store the restore point data.

    However, if the CONVERSION_GUARD configuration parameter is set to 2 and the upgrade to the new version of the server fails, you can use the onrestorept utility to restore your data.

    However, if you set the CONVERSION_GUARD configuration parameter to 2, conversion guard operations fail (for example, because the server has insufficient space to store restore point data), and the upgrade to the new version fails, you cannot use the onrestorept utility to restore your data.

  2. In the RESTORE_POINT_DIR configuration parameter, specify the complete path name for a directory that will store restore point files.

    The server will store restore point files in a subdirectory of the specified directory, with the server number as the subdirectory name.

What to do next

If the CONVERSION_GUARD configuration parameter is set to 1 and an upgrade fails, you can run the onrestorept utility to restore the Informix® instance back to its original state just before the start of the upgrade.

If the CONVERSION_GUARD configuration parameter is set to 1 and conversion guard operations fail (for example, because the server has insufficient space to store restore point data), the upgrade to the new version will also fail.

If any restore point files from a previous upgrade exist, you must remove them before you begin an upgrade.

Even if you enable the CONVERSION_GUARD configuration parameter, you should still make level 0 backup of your files in case you need to revert after a successful upgrade or in case a catastrophic error occurs and you cannot revert.