This topic describes how to reverse the results of the WebSphere
message migration utility.
Before you begin
If you want to revert to using WebSphere Application Server Version
5, instead of WebSphere Application Server Version 6, you must reverse
the migration of the messages before deleting the WebSphere Application Server
Version 6 server.
Why and when to perform this task
Reverse migration is carried out under XA coordination.
If
the reverse migration takes place after a partial migration from WebSphere
Application Server Version 5 to WebSphere Application Server Version 6,
in which only some of the messages were migrated, then the message ordering
will not be preserved. However, if the target queue in the WebSphere Application
Server Version 5 is empty when the migration takes place (as it is likely
to be) then the message order will be retained.
Messages that are reverse-migrated
appear on the queue after those that were not migrated at the first attempt.
Note: - You run the message migration utility only once for a particular queue,
unless a failure occurs.
- If a failure occurs during message migration, it is safe to run the message
migration utility again in the same direction because messages are moved rather
than copied. Whether you successfully retry a failing message migration, or
delete the message, the message ordering of the remaining messages is preserved
on the WebSphere Application Server Version 6 queue.
Steps for this task
- Follow the actions indicated by the message migration utility.
- On the "Select the direction of migration" panel choose Reverse
a previous migration.
As in normal migration, if a queue has a failing message you have
the choice of:
- Retrying the failing message, in case there is a transient error.
- Deleting the failing message and going on to the next message.
- Stopping the queue that has the failing message and moving on to the next
queue.