Migrating IBM MQ

Migration is the conversion of programs and data to work with a new code level of IBM® MQ. Some types of migration are required, and some are optional. Queue manager migration is never required after applying a maintenance level update, that does not change the command level. Some types of migration are automatic, and some are manual. Queue manager migration is typically automatic and required after releases and manual and optional after a maintenance level upgrade that introduces a new function. Application migration is typically manual and optional.

Before you begin

Before upgrading your IBM MQ installation or migrating your queue managers, you must read Changes that affect migration to identify what migration tasks you must plan for.

About this task

Whenever you upgrade IBM MQ to a new release that changes its command level, migration is performed by the queue manager. Whenever you upgrade IBM MQ to a new maintenance or fix level, which introduces a new function using a new command level, you can migrate the queue manager to use the new command level and thereby the new function.

If you start a queue manager running on a later release level, then migration of the queue manager to that release level is required. The migration tasks you must perform to migrate from one release to another are documented in Migrating a queue manager on Windows; see also Changes that affect migration.

[UNIX, Linux, Windows, IBM i]On IBM MQ for Multiplatforms, you cannot easily revert to a previous level of IBM MQ after installation. If you install a copy of IBM MQ obtained from Passport Advantage® or from physical media, the installer uninstalls IBM MQ, if it is present. It then installs the new level of IBM MQ. To revert to the previous level of IBM MQ, you must keep the earlier installation image and any fixes you applied. Then you must uninstall the new level, reinstall the previous release level, and reapply the required fixes. If you have started any queue managers at the later level, they will not work with the restored level of IBM MQ. (Unless you installed a later maintenance level upgrade, not a new release or version: then you could revert to an earlier maintenance level by reinstalling the earlier maintenance level upgrade. Queue manager data is compatible between maintenance levels.) To restore IBM MQ to its previous level, after starting any queue managers, you must first back up the queue managers. You can then restore the backup queue managers after restoring the previous level of IBM MQ.

[Long Term Support][z/OS]On IBM MQ for z/OS® it is possible to backwards migrate from a Long Term Support (LTS) release. For more information, see Backward migration to earlier supported releases of IBM MQ for z/OS.

[Continuous Delivery][z/OS]Backwards migration is not supported for a Continuous Delivery (CD) release on z/OS.