[Info-vax] OpenVMS servers and clusters as a cloud service

[Johnny Billquist]

On 2018-01-06 21:04, Kerry Main wrote:
> 
>> -----Original Message-----
>> From: Info-vax [mailto:info-vax-bounces at rbnsn.com] On Behalf Of
>> Johnny Billquist via Info-vax
>> Sent: January 2, 2018 5:59 AM
>> To: info-vax at rbnsn.com
>> Cc: Johnny Billquist <bqt at softjar.se>
>> Subject: Re: [Info-vax] OpenVMS servers and clusters as a cloud
> service
>>
>> On 2018-01-01 16:45, Kerry Main wrote:
>>
>>> Different culture as well - lets not forget that Windows and Linux
>> typically deploy one bus app or one App service per OS instance. That
>> drives much higher server numbers, but usually at the pain of VM
>> servers that run at 10-15% busy most of the day.
>>>
>>> With OpenVMS, it is very common to run many Apps on one OpenVMS
>> instance.
>>
>> What kind of nonsese is this? Google runs Linux. Do you think Google
>> only runs one app per machine??? They do not. Like I said before,
>> machine management is all automated, including scheduling jobs on
>> machines. And the system knows the load of different applications, and
>> can combine many applications on one machine, as long as there are
>> resources available.
>>
> 
> To clarify - the common model for Linux and Windows is one "business"
> App per server.
> 
> It is very uncommon to run bus apps from different groups on the same OS
> instance. Each group wants there own server instances (P/V).

I'm sorry, but this just shows that you do not know a single thing about 
how Google works, or how Linux is used.

As I said before, Google have all this automated, down to scheduling 
jobs on machines. There is no centralized planning of deployment or 
scheduling. The end result is that you pretty much all the time see very 
different applications/services running on the same machine. It would be 
completely stupid to not make use of existing machine resources, when 
they are sitting idle.

And manually assigning machines to jobs/applications/services would be 
totally impossible at that scale.

> To quote David's earlier reply -
> " If I can run a decent sized company on one VMS system, with all apps,
> with the
> exception of office automation and web servers, does that qualify as
> "many
> apps"?  Warehouse control, order processing, purchasing, forecasting,
> AR, AP,
> GL, database, and more?"
> 
> How many Linux and Windows environments would run all these on one OS
> instance?

Plenty do, if we talk Linux. For Windows, I have no idea.
But you are so far from truth and reality when the comments is about 
Linux that it's almost funny, if it wasn't for the fact that I think you 
are trying to be serious.

> I know many, many (most?) OpenVMS environments where David's example
> here is the norm, not the exception.
> 
> I know of one very large lottery that is still cranking out billions $
> each year on a 2 Alpha server cluster. That homogeneous cluster has
> 15-20 different Apps / DB's running on the two server cluster. I know,
> because they were looking at a move to Integrity (support reasons, not
> performance) and each App had to be looked at for the porting impact
> analysis.

The fact that VMS can do it says nothing about the other OSes.

>> One application per machine is such a nonsensical and uninformed
> belief
>> that it almost blows my mind. I can't comment on Windows at all, but
> in
>> the Unix/Linux world, nothing could be further from the truth.
>>
> 
> See above. More simply - how many Linux/Windows servers would put the
> Web server, App server and DB server on the same single OS instance?

At Google, it happens all the time.
More specifically, any application/service never runs on one machine, 
but is seriously distributed. And they talk to other 
applications/services, that are also spread out over many machines. And 
the whole scheduling of all applications/services are done 
automatically, and pretty much always have lots of services/applications 
running on the same physical machines, for the simple reason that a 
single application/service never keeps a machine fully busy.

>> There is a reason containers have been developed/pushed in Linux. To
>> increase isolation between multiple applications running on the same
>> machine. However, I do think all the knobs in VMS can be very useful
> in
>> this context. Unix sometimes certainly suffer because of the lack of
>> those (hello page quota).
>>
>>     Johnny
>>
> 
> In some respects, containers are an attempt to address the growing
> challenge of VM sprawl i.e. reduce the numbers of separate OS instances.
> 
> Not very well known, but OpenVMS also has an native class scheduler
> which can also be used to ensure certain processes or even groups of
> processes do not take more resources than they are allocated. This is
> another required feature when one looks at App stacking.
> 
> $ mcr sysman
> Sysman> help class
> 
> Also, reference the following:
> <http://h41379.www4.hpe.com/openvms/journal/v15/class_schedule.pdf>
> " The class scheduler provides the ability to limit the amount of CPU
> time that a system's users may receive by placing the users into
> scheduling classes. Each class is assigned a percentage of the overall
> system's CPU time. As the system runs, the combined sets of users in a
> class are limited to the percentage of CPU execution time allocated to
> their class. To invoke the class scheduler, use the SYSMAN interface.
> 
> Class scheduling is implemented in the SYSMAN utility, which allows
> users to define classes based on username, UIC, or account. SYSMAN
> allows users to create, delete, modify, suspend, resume, and display
> scheduling classes."

Containers don't really do much about scheduling, actually. But it 
isolates resource usage in a way that Linux previously did not easily 
handle. VMS have quotas that do a lot of the same thing.
Working sets, for example. As well as file system isolation.

Scheduling with containers still run the same as if you didn't have 
containers.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol