The minimum system requirements for Rocky Linux 10 state that “Multi-core CPUs are recommended for server.”
Does this refer to physical cores, or are logical cores (vCPUs) also acceptable?
vCPU are also acceptable.
thank you for your reply.
Could you please confirm the following:
For example, on Google Cloud, vCPU x 2 are reported to run on a 1 physical core.
When creating an instance with vCPU x 2, does this satisfy the requirement of “Multi-core CPUs are recommended”? or, needs vCPU x 4 ( = 2 physical core ) for recommended ?
FYI : Hyper-threading is enabled.
On my VM with 2 vCPU:
root@rocky9:~# nproc
2
so it doesn’t matter whether it’s physical or vCPU. You could have multiple vCPU on a single core, or a single vCPU from multiple physical cores. It is up to you how you configure the VM and how many CPU/VCPU you want it to see.
As far as I am concerned, my VM has 2 and it works fine. It works fine even if I was to give it only 1.
Thank you for your response.
I apologize for asking multiple questions.
Regarding the phrase “Multi-core CPUs are recommended” on the official Rocky Linux 10 website,
I assume that “multi-core CPU” usually refers to physical cores.
On Rocky Linux 10, if the command nproc on the OS shows a value of 2 or more,
can I consider that the requirement “Multi-core CPUs are recommended” is met,
regardless of whether they are physical or vCPUs?
A “recommendation” does not mean “must”, it is a “would be nice”.
It could well be the documentation needs to clearly explain core/vcpu by listing both. Either way, it doesn’t really matter since I’ve got plenty of VM’s using vCPU than physical cores and none of them have performance issues.
In my opinion you have nothing to worry about by using 2 vCPU like I’ve already written previously in this thread. What you do later with the machine is far more important. The docs list the minimum specs. If you then decide you want to run a database server on it, then you are going to need more CPU/vCPU and RAM than the minimum. So the discussion is relative anyway.
Overall, CPU is not a “hard limit” here. Things just take longer (and overhead of thread switching takes relatively bigger slice when there are less cores).
RAM is a hard limit; when things do not fit in RAM, they don’t.
The hard limit about CPU are the instructions that it supports. If executable is compiled to use certain instruction, then it can run only on CPUs that have that instruction. Examples of that are Rocky 9, which requires instructions defined as “x86_64_v2”, and Rocky 10 that requires “x86_64_v3” (on Intel/Amd x86_64 CPUs).
Everyone, thank you for your helpful responses.
I have learned a lot.
I will be able to use the knowledge gained here to help with server setup.