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Migrating and upgrading
You can upgrade to the 14.10 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Migrating Informix® database systems
The Informix® Migration Guide describes how to move data manually between databases, servers, and computers.
Data migration utilities
The onmode utility reversion option
You use the -b option of the onmode utility to revert to the older database server from which you converted.

Migrating and upgrading
You can upgrade to the 14.10 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
- Migrating Informix® database systems
  The Informix® Migration Guide describes how to move data manually between databases, servers, and computers.
  - Overview of migration
  - Migration to and reversion from 14.10
  - Migration of data between database servers
  - Data migration utilities
    - External tables
      External tables are a fast and versatile method for moving data between database servers. External tables are the fastest method for loading data into a RAW table with no indexes.
    - The dbexport and dbimport utilities
      The dbexport and dbimport utilities import and export a database and its schema to disk or tape.
    - The dbload utility
      The dbload utility loads data into databases or tables that Informix® products created. It transfers data from one or more text files into one or more existing tables.
    - The dbschema utility
      The dbschema utility displays the SQL statements (the schema) that are necessary to replicate database objects.
    - The LOAD and UNLOAD statements
      You can use the SQL LOAD and UNLOAD statements to move data. The LOAD statement is moderately fast and easy to use, but it only accepts specified data formats. You usually use the LOAD statement with data that is prepared with an UNLOAD statement.
    - The onunload and onload utilities
      The onunload and onload utilities provide the fastest way to move data between computers that use the same database server on the same platform.
    - The onmode utility reversion option
      You use the -b option of the onmode utility to revert to the older database server from which you converted.
      - What the onmode -b command does
        When you convert a database server, several modifications make the format of the databases incompatible with the older version. The onmode -b command modifies data so that the earlier version of the database server can access it.
      - Preparation for using the onmode -b command
        Before you use the onmode -b command, notify users that you are going to bring the database server offline. The reversion utility forcibly removes all users and shuts down the database server.
      - Syntax of the onmode -b command
        The onmode -b command restores your databases to the version of Informix® from which you converted. You cannot use this command to revert to any other version of the server.
    - The onrestorept utility
      You can use the onrestorept utility to restore the database server back to the state that it was in just before the start of the failed upgrade.

The onmode utility reversion option

You use the -b option of the onmode utility to revert to the older database server from which you converted.