[Info-vax] Desirable features for VMS

[Marc Van Dyck]

Dave Froble formulated the question :
> On 1/28/2024 8:32 AM, Arne Vajhøj wrote:
>> On 1/28/2024 8:25 AM, Marc Van Dyck wrote:
>>> Simon Clubley formulated the question :
>>>> Does anyone have any others to add to the list ?
>>>
>>> Yes. Some kind of automatic disaster recovery. That is, if a process,
>>> or a set of processes, run on a system that crashes, those processes are
>>> automatically restarted on another cluster member, transparently, with
>>> no manual intervention, and continue from the point they were at when
>>> the system crashed. No transaction lost of any kind, and without having
>>> to add anything in the code that those processes are running. The
>>> operating system (or layered product) does all the work transparently.
>>> Should work with code written 30 years ago, with ACMS applications,
>>> anything.
>>
>> Something like Tandem NonStop lock-step?
>>
>> Arne
>>
>>
>
> Well, no, not really.  What I'd envision would be what I'd call an 
> application monitor, for lack of a better name, that would be able to know 
> what the applications should be doing, to monitor that activity, and to do 
> whatever necessary to continue the activity, should anything happen to that 
> activity. Yeah, non-stop, but not the Tandem design.
>
> Just a concept, and design and implementation might be "interesting".
>
> I'd just note that the OSs would be included as applications, so re-starting 
> them from where they were interrupted would be included in the concept.  So, 
> yeah, the monitor would be outside/over the OSs.  Perhaps something like 
> happens with VMs.  Except VMs want to move the activity to another system, 
> not recover on the same system.

Whatever the design and implementation, this would be a really useful
and marketable addition to the OpenVMS cluster concept. Clusters were
invented 40 years ago to implement horizontal scalability, because
vertical scalability was impossible, technically or financially. This
issue has mostly disappeared today, current hardware being able to
deliver any power we might want. Today's clusters are essentially
put in place for redundancy or disaster recovery purposes ; the next
logical step should be to provide this redundancy in a transparent way
to the system user.

This should also be, as opposed to simple user niceties, something that
allows VSi to make money with.

-- 
Marc Van Dyck