libvirt users - Aug 2019 - Re: CPU and Memory requirements for host OS ( CentOS 7.6) on Dell Poweredge R630 server

Hi,

I am running Dell R630 Poweredge 1U with 32 cores vCPU's and 96 GB
RAM. What should be the minimum numbers of CPU cores and memory that
should be reserved for host OS (CentOS 7.6) and the remaining CPU
cores and memory resources to be allocated for Guest OS?

I look forward to hearing from you and thanks in advance.

Best Regards,

Kaushal

That depends on what you plan on doing with the host. IIRC live VM
migrations use host CPU time, and depending on transport can use quite a
bit of CPU (for encryption/compression). Same with storage, if you have
a ZFS/btrfs/LVM2/RAID/encryption setup that requires a lot of CPU,
that's also counted against host CPU time.

libvirtd itself doesn't need all that much resources for itself, that
said. 2 cores and 2GB RAM should suffice as baseline? Plus whatever you
need to meet above needs, if any apply.

On 26.08.19 20:02, Kaushal Shriyan wrote:
> Hi,
> 
> I am running Dell R630 Poweredge 1U with 32 cores vCPU's and 96 GB
> RAM. What should be the minimum numbers of CPU cores and memory that
> should be reserved for host OS (CentOS 7.6) and the remaining CPU
> cores and memory resources to be allocated for Guest OS?
> 
> I look forward to hearing from you and thanks in advance.
> 
> Best Regards,
> 
> Kaushal
> 
> 
> _______________________________________________
> libvirt-users mailing list
> libvirt-users@redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
> 
-- 
Mit freundlichen Grüßen, / Best Regards,
Sven Schwedas, Systemadministrator
✉ sven.schwedas@tao.at | ☎ +43 680 301 7167
TAO Digital   | Teil der TAO Beratungs- & Management GmbH
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On Tue, Aug 27, 2019 at 1:05 PM Sven Schwedas <sven.schwedas@tao.at>
wrote:
> That depends on what you plan on doing with the host. IIRC live VM
> migrations use host CPU time, and depending on transport can use quite a
> bit of CPU (for encryption/compression). Same with storage, if you have
> a ZFS/btrfs/LVM2/RAID/encryption setup that requires a lot of CPU,
> that's also counted against host CPU time.
>
> libvirtd itself doesn't need all that much resources for itself, that
> said. 2 cores and 2GB RAM should suffice as baseline? Plus whatever you
> need to meet above needs, if any apply.
>
>
Hi Sven,

So for host OS, 2 vCPU's with 2GB Memory is enough. Please comment. I have
spawned 10 KVM based VM's with CentOS 7.6 on the bare metal server (Dell
R630 Poweredge 1U with 32 cores vCPU's and 96 GB RAM.) Is there a way to
find out the system resources utilization for all the 10 VM's?

Best Regards,