It really depends on the workload whether scale-up or scale-out is better
suited. With z/VM 6.3 you should be well prepared for both options (as you
are with running Linux in LPAR) but it is really a workload question. E.g.
many applications would allow for scale-out clustering at linear scale,
while e.g. databases would require for data sharding in a scale-out model
if scale-up is not an option. In any case don't define more vCPUs to a
single virtual machine than you have logical CPUs defined to your LPAR as
also Scott pointed out.
Now this said, if your capacity needs keep growing and the concurrent,
aggregated CPU capacity needs exceed 64 cores (or 32 cores running SMT2
giving you 64 HW threads) you may need spilling over into an additional
z/VM instance anyhow ...
Mit freundlichem Gruß / Best regards
Ingo Adlung
Ingo Adlung IBM Deutschland Research &
IBM Distinguished Engineer Development GmbH
Chief Architect, and CTO Vorsitzender des Aufsichtsrats:
z Systems and LinuxONE Martina Koederitz
Virtualization & Linux Geschäftsführung: Dirk Wittkopp
mail: [email protected] Sitz der Gesellschaft: Böblingen
phone: +49-7031-16-4263 Registergericht: Amtsgericht
Stuttgart, HRB 243294
Linux on 390 Port <[email protected]> wrote on 03.04.2017 15:46:38:
> From: "Wheeler, Mark L" <[email protected]>
> To: [email protected]
> Date: 03.04.2017 15:47
> Subject: [LINUX-390] RHEL 6 CPU Scalability
> Sent by: Linux on 390 Port <[email protected]>
>
> Greetings!
>
> We have eight RHEL 6 servers with 8 vCPUs each handling a large
> workload, which continues to grow. We could expand the server farm
> horizontally by adding more servers, or vertically by adding more
> vCPUs. I'm concerned about SMP effects of adding more vCPUs but
> don't have any data to validate that concern one way or another.
>
> Can anyone provide a recommendation? More servers or more vCPUs?
>
> Very best regards,
>
> Mark Wheeler
> z/VM and zLinux
> Optum Technology
> 952-912-9524
> Mark_Wheeler at optum.com
>
>
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