[libvirt-users] CPU and Memory requirements for host OS ( CentOS 7.6) on Dell Poweredge R630 server

[Peter Crowther]

*may or may not be* enough - a huge amount depends on your workloads.
As ever, watching the available memory and how much CPU is in use in
"top" will give you a better idea of how your infrastructure is
behaving, as will watching the server charts in virt-manager if it's
available.  For example, for some of our workloads, we can overcommit
memory by a factor of two (so run nearly 200G of virtual server RAM on
a 96G machine) and overcommit CPU by nearly a factor of three, and
everything's fine.  For other workloads, they need to get all the
resources we promised them.

Sorry not to give an exact answer; it's a rather similar situation to
"is this machine big enough to run my database server?" but with more
variables.

- Peter

On Tue, 27 Aug 2019 at 17:20, Kaushal Shriyan <kaushalshriyan at gmail.com> wrote:
>
>
> On Tue, Aug 27, 2019 at 1:05 PM Sven Schwedas <sven.schwedas at 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,
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