Mark,

Backwards migration is supported between LTS releases (i.e. 9.0.0, 9.1.0,
9.2.0), so it's not correct that the upgrade process is not reversible,
unless the question is about a CD release.

IBM always suggested being up-to-date with all maintenance before migrating
to a new release. The backwards migration process has changed in 9.2, and
there is no need to apply a specific backwards migration PTF before
migrating. The backwards migration process in 9.2 is documented here:
https://www.ibm.com/docs/en/ibm-mq/9.2?topic=92-reverting-queue-manager-previous-version-zos
.

All the MQ on z/OS migration information is documented under this topic:
https://www.ibm.com/docs/en/ibm-mq/9.2?topic=mq-migrating-zos


The question about backing up your page sets and logs is an interesting one.

If you backed up your page sets, and restored a pageset,  (and did not
restore your logs from backup) then when you restart the queue manager it
would replay the logs and bring the restored page set(s) up to date.

If you back them up, go to the next release, run for a day and then decide
to use your backups of page sets AND LOGS ( so your logs now do not have
any updates since the backup)
This causes problems like Messages which had been in the system, and
processed - now appear again (from the backup) - so where the message said
"PAY COLIN $1000000" would get processed twice.
Any new messages which were not processed before shutting down and
restoring would be overwritten by the restore.
Any channels going to other queue managers which had sent messages, will
get sequence number mismatches and you will have to reset the channels.

So the lesson is, you can ( and should backup) your pages sets, but *do not
try to restore the logs from backups* except under IBM's guidance.
(As a good sysprog you will have tested the backup and restore of a page
set - and have JCL already written to do this!)

regards

Colin





If you were on LTS, you could go from 9.0 to 9.1 and back to 9.0 without
losing any messages.






On Tue, 27 Apr 2021 at 16:52, Steely.Mark <[email protected]> wrote:

> Has anyone upgraded from MQ 9.0 to 9.2 ?
>
> Is there any PTF's that need to be applied to 9.0 before going to 9.2.
> This is the only thing I have found:
>
> While at MQ 9.0, take a full backup of the queue managers. Why? Because
> the upgrade process is NOT reversible. If you need to revert back from MQ
> 9.1 to 9.0, then you must delete the queue managers and restore the backup
> taken at MQ 9.0.
>
> I know this statement is talking about 9.1 but I think it would also
> relate going to 9.2.
>
> Any information relating to upgrading MQ would be appreciated.
>
> Thank You
>
>
>
>
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