[Info-vax] upgrading to VSI VMS---and back

[Bob Gezelter]

On Thursday, January 6, 2022 at 6:51:53 AM UTC-5, Phillip Helbig (undress to reply) wrote:
> I want to upgrade to VSI VMS. However, I'm worried that---like those 
> with commercial VSI licenses---at some point licenses will no longer be 
> available (at reasonable cost). I am somewhat unusual as a hobbyist in 
> that I actually bought some commercial licenses back in the day, so if 
> worst comes to worst I can continue to run a hobbyist cluster (though 
> only with a couple of small machines with an old version of VMS). If I 
> upgrade to VSI with the community license, the only way to fall back on 
> that would be to restore the old 8.4 system disks. That would also mean 
> that any code which makes use of new features would no longer work. 
> 
> Something of a compromise would be a mixed HPE/VSI cluster. I don't 
> think that that is supported (probably not much of an issue for a 
> hobbyist cluster), but it won't even technically work, right? That also 
> means that a mixed-cluster rolling upgrade won't work, so the upgrade is 
> more difficult than usual, and the downgrade as well. 
> 
> Of course, the ultimate goal is to move to x86, but then going back to 
> HPE Alpha would be even more work. 
> 
> Of course VSI seems enthusiastic about VMS and we all hope that it will 
> continue, but people remember DEC disappearing, going from strength to 
> non-existence in just a few years, the promise of the 20-year 
> development lifetime for Alpha, and so on.
Phillip,

The last version of HPE OpenVMS is Version 8.4, with UPDATE 15 being the terminal update. 

I am personally maintaining an IA64-based mixed version OpenVMScluster running with 8.4 and 8.4-2L3 inter-operating on a minute to minute basis without incident, with each version having a separate system volume.

As a mixed-version OpenVMScluster it is, as I recall, supported technically. Check the SPD on vmssoftware.com for the official position.

Direct upgrade of a system volume is supported, providing that the 8.4 system is at a minimum update level, the  Installation and Upgrade manual for the  VSI release is explicit on that point.

As to x86-64, my recollection from presentations is that Alpha/x86-64 and Itanium/x86-64 was "supported", but that  Alpha/Itanium/x86-64 was not, but I seem to recall seeing a SHOW CLUSTER output with all three active. 

- Bob Gezelter, http://www.rlgsc.com