I recently wrote about how OPMODE works in the Long Term Service (LTS) release of MQ V9 on z/OS, and the differences compared to previous versions of MQ.
The operation of OPMODE is quite different again in the Continuous Delivery (CD) releases of MQ V9, and that’s what I want to describe now.
So what’s different?
From V9, MQ has moved a continuous delivery support model. This means that in addition to the LTS release for installations where only defect fixes are required, several CD releases per year will be delivered, containing incremental changes to functions. MQ V9.0.0 is an LTS release. MQ V9.0.1 and MQ V9.0.2 are CD releases.
The big difference between the LTS and CD releases of MQ V9 is that you cannot fall back to a previous release of MQ after migrating to a CD release. So if you migrate from MQ V8.0 to MQ V9.0.1, for example, you cannot start the queue manager again at MQ V8.0. This is a change to how MQ on z/OS has behaved in the past – backwards migration to a previous level of MQ has always been supported, and still is in MQ V9 LTS (provided that the value of OPMODE allows it, of course).
You have to explicitly allow the queue manager to start at a CD release using OPMODE, as I’ll describe below, to prevent you from accidentally starting the queue manager at a CD release.
New functions are always available
If a CD release queue manager can never be started at an earlier release of MQ, then it follows that new functions in the latest release can always be available, even if they are incompatible with previous releases of MQ. Therefore, a CD release queue manager will always run in NEWFUNC mode.
When to recompile the ZPARMs
To start a CD release queue manager you need to have first recompiled the ZPARMs with OPMODE=(NEWFUNC,90x), where x is 1 or higher, denoting a CD release of MQ V9. This makes sure that you don’t unintentionally start a queue manager at a CD release, and therefore lose the ability to go back to a previous release.
To make your life a bit easier, you only need to do this the first time you migrate your queue manager to a CD release. When migrating between CD releases, from MQ V9.0.1 to MQ V9.0.2 for example, you do not need to change the value of OPMODE or recompile the ZPARMs again.
The big difference between migrating to a CD and an LTS release of MQ V9 is that when migrating to a CD release of MQ for the first time you must recompile your ZPARMs to set OPMODE to a new value. When migrating to an LTS release of MQ V9, do not recompile your ZPARMs (for reasons described in my previous post).