Planning for New ESXi Hosts - Which CPU Metrics Should I Use?
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I am finally planning out the configs for 2 new ESXi hosts (replacing Dell R720XD with R740XD). I have gotten to an area where I am not sure which metrics I should use to decide on CPU. The majority of VMs are Windows Server and running a standard array of file/print servers, ADDCs, databases, RADIUS, RDS, etc.
I have had Veeam One monitoring my current environment for years, so I can go back and look at resource usage over time. What should I be looking for to decide on higher clock rate vs more cores?
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Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
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Licensing is the big thing here. Is your licensing by host, core, or socket? Since your running Windows on top and vsphere you'll need to be concerned with both core and socket.
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ALl things being equal, high clock speeds are better than cores when they are directly equal (e.g. double clock speed vs. double cores.) But that basically never comes up. In modern workloads, cores are normally better. But Windows makes them costly, so on Windows, all bets are off. Basically you want cores until you get to 16. Then you want clock speed until you have to have more cores.
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@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
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@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
I could have sworn it was 8. Did it used to be 8?
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
I could have sworn it was 8. Did it used to be 8?
No, never was.
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
I could have sworn it was 8. Did it used to be 8?
Eight... per socket. There is this weird thing where people in the SMB space for some reason assume all servers are two sockets when 1, 2, 4, 8.... are all just as valid. So they say "8 core CPUs" meaning 2x8=16. But they add this totally BS assumption that makes it make no sense.
So 1x16 or 2x8 are both 16 cores.
It was 16 cores since MS first moved from socket to core licensing.
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@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
I could have sworn it was 8. Did it used to be 8?
Eight... per socket. There is this weird thing where people in the SMB space for some reason assume all servers are two sockets when 1, 2, 4, 8.... are all just as valid. So they say "8 core CPUs" meaning 2x8=16. But they add this totally BS assumption that makes it make no sense.
So 1x16 or 2x8 are both 16 cores.
It was 16 cores since MS first moved from socket to core licensing.
That is why. I conflated the 2x8 and just took the 8.
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So if I had 1 socket with 16 cores, I would be fine. If I had 2 sockets with 16 cores, I would need an additional Windows Server license for the other 16, correct?
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
So if I had 1 socket with 16 cores, I would be fine. If I had 2 sockets with 16 cores, I would need an additional Windows Server license for the other 16, correct?
Yes. See the following page: https://www.microsoft.com/en-us/licensing/product-licensing/windows-server
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vSphere is different.
They license per socket.
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@coliver Thanks. I figured that was the case. Maybe that is where I got 8 from.
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@coliver said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
vSphere is different.
They license per socket.
Right. I currently have vsphere essentials plus with 6CPUs. 3 servers with 2-sockets each.
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
@scottalanmiller said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
Clock Rate vs Cores is a combination of your threading needs and your licensing costs.
Well, it is Windows, so... I will definitely need to add a couple additional licenses for anything above my current setup of dual 4-core servers.
No, actually Windows licensing is flat from 1 core to 16 cores. You are at 8 currently, so in the middle of the "minimum" range.
I could have sworn it was 8. Did it used to be 8?
Eight... per socket. There is this weird thing where people in the SMB space for some reason assume all servers are two sockets when 1, 2, 4, 8.... are all just as valid. So they say "8 core CPUs" meaning 2x8=16. But they add this totally BS assumption that makes it make no sense.
So 1x16 or 2x8 are both 16 cores.
It was 16 cores since MS first moved from socket to core licensing.
That is why. I conflated the 2x8 and just took the 8.
Almost everyone does
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@wrx7m said in Planning for New ESXi Hosts - Which CPU Metrics Should I Use?:
What should I be looking for to decide on higher clock rate vs more cores?
Most servers (VMs) idle almost all the time in which case it makes most sense to configure the hypervisor with a high number of cores, automatically making them slower cores. That way you can handle lots of VMs concurrently.
If you have workloads that have performance limitations, meaning you want them to be faster, higher speed cores are needed. While almost all applications are multithreaded, bottle necks often depend on a single core performance.
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As you have several hosts it could make sense to have one dedicated to high performance VMs and one to lots of lower performance VMs. Then you have the possibility to move the VMs depending in what type of workload it is.
That's what we have done. Database hypervisors have higher performance and run on NVMe storage while the others are lower performing and run ordinary SSDs.
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If your going with Intel, make sure you get second gen scalable CPUs. They have 2 in the second number of the CPU.
So 5218, 6242 8276 etc.
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Pick from the left column for performance:
