If you install version 11.50xC6 or a later version of Informix and then upgrade to another new Informix version or fix pack, you can enable the server to use the onrestorept utility to restore the server to a consistent, pre-upgrade state if the upgrade fails. If you enable the server to use this utility, you can undo changes made during the upgrade in minutes (and in some cases, in seconds). Previously, if a fix pack upgrade failed, you had to restore the database by using a level-0 archive.
You use the new CONVERSION_GUARD and RESTORE_POINT_DIR configuration parameters, which are documented in the IBM Informix Administrator's Reference, to specify information that the onrestorept utility can use if an upgrade fails.
For information on the onrestorept utility and setting up the server for it, see the following topics in the IBM Informix Migration Guide: