VMware's recommends 4-8 vCPUs per core - so with your configuration dual quad cores cpus VMware's recommendation would be 64 at most - If you have 50 dual vCPU VMs on a dual quad core host you will probably run into CPU contention because your are talking 100 vCPUs - but you also have an added problem that can and will affect. Perform always a loadtest with third-party tools like Loadgen or LoginVSI to. ESX server "owns" all physical resources including all cores/cpus. preferHT=True – For all VMs to use hyper-threading with NUMA, add the following configuration on the ESXi Host Advance settings: numa. This tool calculates the number of hosts in a vSphere ESXi cluster based on the planned VM workload and host configuration. coresPerSocket larger than 64 will result in a. LOGICAL PROCESSOR = Amount of CPU's presented to the ESX HostA virtual machine cannot have more virtual CPUs than the actual number of logical CPUs on the host. Microsoft recommends that you maintain a one-to-one ratio of virtual processors to physical CPU cores. e. vcpu. Powering on a VM with a manually configured value for cpuid. For example, if a virtual machine with one virtual CPU is running on a host that has four physical CPUs and the CPU usage is 100%, the virtual machine is using one physical CPU completely. 2 Replies. 7GHz base clock and a 5. 2) If you have an allocation pool with 12 GHz CPU allocation and a CPU speed of 1 GHz, the customer can use 12 vCPUs (12 * 1 GHz). In the most simplest form, maybe think of it this way. 5 to show CPU Ready. In general, 1 vCPU is not equal to 1 CPU. Administering CPU Resources in vSphere. + (Average RDY Core 3) Because ESXi assign CPU resources to each machine when CPU cores available for all machines' cores, machine has 4 cores, so it has to wait for 4 core of physical cpu. The calculator will then output the. multiple vCPU helps some time when you have native multithreading application (SQL, Exchange). 50 : 1 :As an informal initial sizing approach, to start, assume that each virtual machine requires 1/8 to 1/10 of a CPU core as the minimum guaranteed compute power. Always ensure that the size of the physical CPU and. Number of CPUs. Using the command line, run “esxtop”. When determining how many vCPUs to assign to an Exchange Server VM, always size assuming 1 vCPU = 1 physical core. 0GHz turbo boost. 1. But performance problems can occur much earlier. Also, a vCPU has been traditionally presented to the guest OS in a VM as a single core, single socket processor. Unfortunately, Converter will take the number of physical cpus, and setup your VM with that number of vCPUs. Let me tell you why. - if you have a request for 4 CPUs then you need. This gap makes it especially. As shown below, the VM pictures has eight vCPUs – two vSockets each of which has four cores. At work on ESXi, with Xeon 5600 (hex-core) CPUs, we can run 20-50 VMs per server (all running off large, expensive SANs). In these cases, keep the CPU overcommitment ratio vCPU-to-pCPU less. CPU sizing VM/core vCPU/core best practice. By default, vSphere manages the vCPU configuration and vNUMA topology automatically. VMware uses the terms virtual CPU (vCPU) and physical CPU (pCPU) to distinguish between the. The physical CPUs are owned and coordinated by the hypervisor and it divides the CPU into these. A physical core is just that: the phsical hardware. CPU ready is a reliable metric to determine when or if you have truly overprovisioned your pCPU's. To calculate virtual machine CPUs within the vSphere Client, multiply the number of sockets selected by the number of cores selected. e. VMware refers to CPU as pCPU and vCPU. . To the guest OS it looks like a real CPU but on the Hypervisor (ESXi, VMware Workstation,. 1 vCPU = 1 core per socket. With this change, VMware is still using the per-CPU licensing model, but we will require one license for any software offering that we license on a per-CPU basis, for up to 32 physical cores. Select Unlimited to specify no upper limit. You should set cores per socket equal to vCPU until it gets larger than the cache domain, then it’s equal to the cache domain. AWS: Each vCPU is a thread of a CPU core, except for. VMware vSphere enables you to consolidate multiple workloads in the form of virtual machines on a single physical host. esxtop reports ready time for a VM once its been summed up across all vCPUs. Determining this ratio will depend on the CPU utilization of the workloads. VMware SD-WAN Gateway is a data-plane intensive workload that requires dedicated CPU cycles to ensure optimal performance and reliability. Adding this detail for the forum users who might find it. 1 Physical and Virtual CPUs VMware uses the terms virtual CPU (vCPU) and physical CPU (pCPU) to distinguish between the processors within the VM and the underlying physical processor cores. Just a basic calculator how to size your physical hardware environment based on the amount of requested virtual cores per cluster (vCPU/CPU ratio) to avoid high CPU ready values. For ESXi 7. Note: Remember that 1 vCPU maps onto a physical core not a physical CPU, so the virtual machine is actually getting to run on 4 cores. Unfortunately I have seen this sometimes referenced as VM/core and other times. That's all you are doing. The Desired Availability Level (N+x) Next enter the total number of vCPUs and vRAM assigned (or expected to be) assigned to VMs in the cluster. idleLoopSpinUS parameter you can edit the vmx file while the VM is powered off or: Shut down the virtual machine. License for each processor license is flexible for up to 32 physical processing cores per CPU. a physical CPU is namely corresponding to 1 core (embedded in a CPU socket) a VM machine (or a guest OS) recognizes/handles its CPUs always at a virtual CPU level (a virtual CPU is noted as vCPU below). Q1 Please clarify if following understanding of mine is correct or not: a physical CPU is namely corresponding to 1 core (embedded in a CPU socket) a VM. The number of cores and threads of an Intel processor can be found in the Intel's Technical Specifications website by searching by processor number. Avoid hot-plugging vCPUs: Hot-plugging is the process of adding vCPUs to a VM while it is. Each CPU socket contains a CPU package with 10 CPU cores. Number of vCPU – Number of virtual CPUs per desktop. Microsoft provides guidelines to calculate the required compute resources for a single instance of Exchange Server (as an application) so that. This threshold cannot be overtaken because Hyper-V is. VMware is one of the top virtualization software that allows you to create virtual machines and make the best use of your resources. vSphere attempts to keep the VM within a NUMA node until the vCPU count of that VM exceeds the number of physical cores inside a single CPU socket of that particular host. A virtual machine cannot use more CPU cores than the number of logical processor cores on a physical machine. We generally use the calculation of 8 vCPU's per logical processor (on Hyper-V. If not known leave as Default. Additionally, VMware enables you to move these virtual machines across hosts with VMware vSphere vMotion®, VMware Distributed Resource Scheduler™ (DRS) and High Availability (HA). Therefore, the formula for calculating the vCPU count is: (Threads x Cores) x Physical CPU Number = Number of vCPUs. 4. A Hyper-V vCPU is not a 1-to-1 mapping of a physical core. Host > Hardware > CPU and check the value of Cores per socket to determine if your host has more than 32 physical cores per CPU. CPU affinity is the same as pinning a process in Windows. Total number of assigned vCPUs to a VM is calculated as:With allocation ratio of 2:1 (2 vCPUs to every pCPU) you can allocate 128 vCPUs, but take in mind to avoid allocate more vCPU to a single virtual machine than it needs, always start small and add new vCPU only when needed. vSphere 7u1 is limited to 4096 vCPUs or 32x core count. 3% of the total CPU power of host. In other words, if there is not enough pCPU for the VM, it cannot be started. 2 Defining an Appropriate RPO. For example, A 8 cores/ 16 threads CPU has (16 Threads x 8 Cores) x 1 CPU = 128 vCPUs. pCPU) X (2 cores) = # Virtual Processors (vCPU) Total CPU resources required for virtual machines at peak:A Hyper-V vCPU is not a 1-to-1 mapping of a physical core. In older versions of VMware Workstation, the maximum CPU count was typically limited to 2 or 4 virtual CPUs per virtual machine. 625 % per vCPU. Cisco design docs say that ESXi reserves approximately 1 core for itself and to take that into account. For a low latency VM without vHT, each vCPU of the VM has exclusively affinity to a thread of the physical core. If you have a physical CPU running at 2. and basing it on purely vCPU then 8 would be minimum but would give little room for moving machines around for patching ESXi, covering off high CPU workloads or providing resilience for potential hardware failures, I would recommend a minimum n+1 so 9 hosts. Put the . VDI Calculator. If your virtual machine still experiences performance issues, and if its kernel or HAL can handle switching to a single vCPU, lower the vCPU count to 1. If it matters, I am looking at vmWare for the virtualization implementation. SOCKET = Physical hole where in one Processor can fit in. VMs with more than one vCPU1. 1. vcpu. A vCPU is a virtual core that is assigned to a virtual machine or a physical processor core if the server is not partitioned for virtual. 2 Defining an Appropriate RPO. 5K user OVAs" since those are 2 vCPU each. A short spike in CPU usage or CPU ready indicates that you are making the best use of the virtual machine resources. The maximum number of processor cores that can be assigned to a single VM is 768 in vSphere 7. One vCPU is equal to whatever the frequency of the physical CPU of the host on which the VM is running, regardless of how many cores there are. Per virtual machine licensing. Based on design, VMware ESXi can handle the CPU oversubscription (request of vCPU more than. If you need the full power of a single core for every virtual CPU, then you should avoid over-commitment. I think you are over thinking this. Go to the Performance tab and select CPU from the left column. It is recommended to start with 1:1 vCPU-to-pCPU ratio, and then scale up the number of vCPUs while assessing performance. Step 1: Determine the total number of vCPUs to allocate to the virtual machine. pCPU) X (2 cores) = # Virtual Processors (vCPU) Total CPU resources required for virtual machines at peak: Without knowing other information like memory network capacity, processor usage etc. André. I have an ESXI server, it has 6 logical CPU(the physical CPU does not support HypterThreading), and 5 vCPU have been assigned to the VM's, when i tried to power on a VM with 2 vCPU, i got the following error(see the attachment). cpu. To the guest OS it looks like a real CPU but on the Hypervisor (ESXi, VMware Workstation,. VM CPU RDY=(Average RDY Core 1) + (Average RDY Core 2) +. e. Select the VM in question. Without knowing other information like memory network capacity, processor usage etc. Percentage of physical CPU core cycles used by the resource pool, virtual machine, or world. Navigate to a virtual machine in the inventory and click Actions. Then each vCPU would get 16. High %RDY and high %CSTP indicate an over-allocation of CPU resources – i. Under the Core per Socket field, enter the total number of cores you would like to allocate to a socket. g. I have yet to find anything conclusive; in fact, I've found a lot of information that is contradictory. Each physical processor (CPU) in a server needs to have at least one processor license key assigned to be able to run vSphere. 2 Replies. A virtual machine cannot have more virtual CPUs than the actual. A CPU is a physical chip that is installed in a computer. 8 Cores x 8 = 64 vCPUs. Put simply, the vCPU:pCore ratio assumes the N+1 host is not in the cluster which is how I personally size environments, especially for business critical. To calculate the number of vCPUs required for a particular workload, first determine the number of physical CPU cores available on the host. For example, a cluster has two hosts, each of which has four CPUs that are 3 GHz each, and one virtual machine that has two virtual CPUs. The number of logical CPUs means the number of physical processor cores or two times that number if hyperthreading is enabled. e there are 112 vCPUs allocated. Also, it is important to mention that there is a limitation in the assignation of vCPU which is related to the license of the vSphere you are using. A generally accepted ratio is 4:1 vCPU to pCPU (excluding HT). The math is rather straight forward. In Google Cloud, a vCPU is typically equivalent to one physical CPU core. If you have an eight-vCPU server, you need two SQL. LOGICAL PROCESSOR = Amount of CPU's presented to the ESX Host A virtual machine cannot have more virtual CPUs than the actual number of logical CPUs on the host. All vSphere ESXi versions up to 7. Follow the sizing implications in the following table to convert CPU. I am trying to understand vCPU concept in VMware. Specifically: - if you have a request for 3 CPUs then you need to specify 3 VCPU and at least 0. . Share. Resolution. That's simple: if you have 32 parallel threads running, but only 20 cores, each thread gets only 62. To start with Physical component. e. Under Hardware, expand CPU to view the information about the number and type of physical processors and the number of logical processors. . For VPCs: 1 VPC equals 1 virtual CPU (vCPU); subject to the “lower of” rule above. ESXi supports virtual machines with up to 128 virtual CPUs. VMware multicore virtual CPU support lets you control the number of cores per virtual socket in a virtual machine. A virtual machine can see vm. Some operating systems will have a maximum on number of vCPUs. Select Unlimited to specify no upper limit. e. 1) If you want to add more counters, the configuration file must only contain the new counters. the others VM will be licensed if i. It is recommended 1 vCPU for task users and 2 vCPU for knowledge users. 3 Multiple Point-In-Time Instances 4. That means that 5% ready on each of four vCPUs will be reported as 20% ready at the VM level. The remaining 15 host physical CPU cores and their thread siblings will be used for shared guest vCPU usage, with an 8:1 allocation ratio for those physical processors used for shared guest CPU resources. Enabling hyperthreading will show 16 logical cores. cores. Before you power on the VM, you can set the VM to 1 vCPU, and then you are setup at the hardware level. Virtual core —Equal to a CPU and viewed by an operating system as a separate processor unit. 0 Update 1. Starting with vSphere 7. 2. A pCPU with 6 logical processors can support up to 48 vCPUs in a non-Windows 7 VDI scenario, e. vNUMA on vSpherephysical processor counts. For the 55xx or newer CPU models, enabling HyperThreading will make a noticable difference. Total RAM per host 6. (approximately 120-125 mins) In both cases, the application utilizes between 90-100% of a single CPU throughout the jobs run-time. Using multicore virtual CPUs can be useful when you run operating systems or applications that can take advantage of only a limited number of CPU sockets. For example, if the physical host contains a single 10-core CPU package, do not assigned more than 10 vCPU to the Exchange Server VM. Now I am going to power off the RHEL and Windows VM and set the vCPU to 2 and re-run the cpu load scripts to see if there is any difference in %RDY and %CSTP values. This way, we have the four vCPUs pinned to physical cores and also using them in exclusivity, in the same NUMA. In vSphere, administrators assign CPUs to virtual machines in order to support the workload needs of each individual virtual machine. ) it maps to a single core. More vCPUs assigned to a VM means that VM is allowed more processing time, and can eat up more total physical CPU resources. This is documented in Hardware Features Available with Virtual Machine Compatibility Settings under: "Maximum number of cores (virtual CPUs) per socket". I choosed to run 4 threads on 2 vCPU in windows VM. The reservation “reserves” CPU resources measured in Mhz, but this has nothing to do with the CPU scheduler. The CPU reservation for low latency VM is. / October 18, 2021 / Uncategorised, VMware. Either way I would see this as 4 vCPU in Azure. I have yet to find anything conclusive; in fact, I've found a lot of information that is contradictory. # of Threads 20 < < < This is number of vCPU you can assign with hyperthreading. 5 as well. I am often asked by customers, vendors or internal teams to explain CPU capacity planning for large production databases running on VMware vSphere. Each vSphere license has a certain capacity that you can use to license multiple physical CPUs on ESXi hosts. 1. Then we add in the memory we need to run vCenter in a virtual machine (8GB plus 342MB), and also figure 1GB for ESX or ESXi per server. Two vCPUs will be two cores or sockets, depending on how you configure it inside the guest, and will. PROCESSOR = CPU. For example, a cluster has two hosts, each of which has four CPUs that are 3 GHz each, and one virtual machine that has two virtual CPUs. The number of physical CPUs that are present in hosts is dependent on a couple factors. Virtual core —Equal to a CPU and viewed by an operating system as a separate processor unit. Are we saying: 1) 0-50msec ( acceptable) 2) Anything between 50msec-1000msec is abnormal, but it should not impact performance. One vCPU is equal to whatever the frequency of the physical CPU of the host on which the VM is running, regardless of how many cores there are. e is dual core). The formula is: 1 (processor) * 2 (core) * 2 (threads) = 4; so, I could create a virtual machine with maximum 4 vCPU. This value indicates that virtual machines may run on any host in the cluster and that you are abstracting the resources at a cluster level rather than a single physical host level. The limitation for the free Hypervisor is a maximum of 8 vCPUs per virtual machine. If your pCPU is 3. 02-14-2007 05:52 AM. VMs with more than one vCPU are also called symmetric multiprocessing (SMP) VMs. Ignore threads, it just the physical cores what matters. A short spike in CPU usage or CPU ready indicates that you are making the best use of the virtual machine resources. 10-11-2021 01:55 AM. If you have one socket and six cores per socket then you have 12 logical processors with hyperthreading. As a result, a Windows host sees 2 CPUs, each one having about 50% of total CPU power. 00. For example, if a four-CPU host is running a virtual machine with two CPUs, and the usage is 50%, the host is using two CPUs completely. The maximum value of the CPU slider is the cluster's total CPU capacity. vCPU MHz Overhead – This setting prevents CPU oversubscription. 5GHz CPUs in the host, but the guest OS in the VM is consistently requesting to be scheduled for 3. To calculate the maximum value, this is the formula: (Number of processors) * (Number of cores) * (Number of threads per core) Check this example of my machine – figure 2. If you have many more VMs on that host that can lead to a high CPU ready time and a very slow VM. The rule of thumb when allocating CPU’s to a Virtual Machine (Best Practice) is to allocate 1 vCPU and then test the CPU utilization. In that case, adding a vCPU to the VM may provide. VMware refers to CPU as pCPU and vCPU. If you have a 4 vCPU VM and it never exceeds 50% usage then it would be better off with 2 vCPU's. VMware vSphere 8. This is called "over provisioning", and is a valid technique to use. ESXi Host CPU and CPU Overcommitment. BTW if your search inside the community, you can find many related topics about CPU Sockets and cores relation, like the following links: pCPU vs vCPU - Relation/Ratio. This guide is the 2021 edition of the best practices and recommendations for SAP HANA on VMware vSphere®. A safe ratio is ~4:1 ratio (vCPU:pCPU). The average virtual machine profile is: 4 vCPU and 4GB to 18GB RAM. HI, Since Microsoft moved to per core licensing i. Configuring Multicore Virtual CPUs. For example, if a virtual machine with one virtual CPU is running on a host that has four physical CPUs and the CPU usage is 100%, the virtual machine is using one physical CPU completely. If you. Turn off CPU and Memory Hot Add, it's more trouble than it's worth. 128 vCPUs/4 vCPUs per VM = 32 VMs. Utilization should generally be <= 80% on average, and > 90% should trigger an alert, but this will vary depending on the applications running in. 3). , "Windows Server 2016 is licensed under the Per Core + Client Access License (CAL) model". These are advanced settings designed to help workloads that are cache-intensive, but not CPU intensive. What you might not have thought about is that the guest operating systems. 7GHz base clock and a 5. Use the vSphere Cluster Sizing Calculator to confirm overcommitment ratios for your cluster or to validate your design. CPU usage is the average CPU utilization over all available virtual CPUs in the virtual machine. Watch performance over several days and use 95th percentile to remove spikes. multiple vCPU helps some time when you have native multithreading application (SQL, Exchange). Answers. Click CPUs. Therefore, to get the CPU ready % from the ms value reported by vSphere, use the formula below: CPU ready % = ( (CPU Ready summation value in ms / number of vCPUs) / (<chart update interval in seconds, default of 20> * 1000 ms/s. SOCKET = Physical hole where in one Processor can fit in. 2 Site Recovery Manager Inventory Mappings. 16 vCPU / 1 vCPU = 16 VM’s. For example, "0,2-4,7" would indicate processors 0, 2, 3, 4 and 7. This calculation depends upon how many virtual CPUs you need per virtual machine. For hosts with Hyperthreading activated, the partner hyperthread has exclusive affinity to an idle world. The answer is, Yes and No. 1) If you want to add more counters, the configuration file must only contain the new counters. Select VMs. e. Here, we select Intel Xeon E-2288G as the underlying CPU. Yes, you can reserve the affinitized CPU to be exclusively used by that VM by selecting "HyperThreaded Sharing" option to "None" while on the CPU Affinity settings screen. This is very similar to how a mainframe works. To upscale we are thinking of adding more DL385's and installed more memory on all the servers. You’ll see the number of physical cores and logical processors on the bottom-right side. I'd suggest decreasing the vCPU count on that VM and reviewing utilization thereafter. There are only 4 execution resources available. Continuous Availability (CA) allows the cluster nodes to be stretched across two fault domains, with the ability to experience up to one fault domain failure and to recover without causing cluster downtime. For ESXi 7. (ESXI Installed). 2. A good rule of thumb for a VDI pilot is that you should start out with each virtual machine defined by using 1/8 per vCPU of a CPU core at minimum. We use this value to calculate disk space required for swap files. Virtual socket —Represents a virtualized physical CPU and can be configured with one or more virtual cores. Put simply, the vCPU:pCore ratio assumes the N+1 host is not in the cluster which is how I personally size environments, especially for business critical. Under Scheduling Affinity, select physical processor affinity for the virtual machine. The socket or sockets used by a virtual machine are dedicated to that virtual machine i. Your Virtual Server includes 24x7 support for the virtual infrastructure, generator-backed power and other benefits of Data Center hosting and operating-system licenses for Windows Server. Click CPUs. As an informal initial sizing approach, to start, assume that each virtual machine requires 1/8 to 1/10 of a CPU core as the minimum guaranteed compute power. How does VMware calculate total vCPU? 4 vCPUs per VM. Today, vCPU count is largely determined by the manufacturer. Without knowing other information like memory network capacity, processor usage etc. 5, so I'm assuming that 4vCPU vSphere is out performing than 3. When you assign a CPU t a VM in it's settings, this is called a vCPU. 1 vCPU, requests are processed quickly. and basing it on purely vCPU then 8 would be minimum but would give little room for moving machines around for patching ESXi, covering off high CPU workloads or providing resilience for potential hardware failures, I would recommend a minimum n+1 so 9 hosts. / October 18, 2021 / Uncategorised, VMware. (16 Threads x 8 Cores) x 1 CPU = 128 vCPU. Yes, you can reserve the affinitized CPU to be exclusively used by that VM by selecting "HyperThreaded Sharing" option to "None" while on the CPU Affinity settings screen. Google: For the n1 series of machine types, a vCPU is implemented as a single hardware hyper. For purposes of this blog post and the way VMware works, a vCPU represents the total amount of CPU resources assigned to a VM. How does VMware calculate CPU? To calculate the number of logical CPUs in vSphere Client, multiply the number of sockets by the number of cores. A virtual central processing unit, virtual processor, or vCPU is a physical CPU assigned to a virtual machine (VM). 4 vCPUs = 4 cores per socket. If workloads are CPU-intensive, the vCPU-to-core ratio will need to be smaller; if workloads are not CPU-intensive, the vCPU-to-core ratio can be larger. A typical vCPU-to-core ratio for server workloads is about 4:1—four vCPUs allocated for each available physical. A typical vCPU-to-core ratio for server workloads is about 4:1 — four vCPUs allocated for each available physical core. That was accomplished giving half of CPU cycles to each logical CPU. These virtual processing resources are pulled from the host’s available physical CPUs. The number of physical cores i. 8 Cores x 2 (Hyper Threading) = 16 x 8 = 128 vCPUsAvailable from 9. The physical CPUs are owned and coordinated by the hypervisor and it divides the CPU into these. When a virtual machine is scheduled, its virtual processors are scheduled to run on physical processors. 1 Physical and Virtual CPUs VMware uses the terms virtual CPU (vCPU) and physical CPU (pCPU) to distinguish between the processors within the VM and the underlying physical processor cores. 6% and the other getting 33. Not all. # of Cores 10 < < < This is number of vCPU you can assign without hyperthreading. any cores limitation for the free ESXI server? 11-20-2021 03:04 AM. - Virtual CPU >= Physical CPU. Each vCPU is mapped to a logical processor, which is a physical core on your host system if you. Press c for the CPU view. The vNUMA blog series by Frank. followcorespersocket: If set to 1, reverts to the old behavior of virtual NUMA node sizing being tied to. Don’t turn on vCPU Hot Add unless you’re okay with vNUMA being turned off. For the best performance, when you use manual affinity settings, VMware recommends that you include at least one additional physical CPU in the affinity setting to allow at least one of the. Don’t create a VM larger than the total number of physical cores of your host. The calculator is designed to be conservative and show information assuming the resources (CPU/RAM) required for the configured availability level are removed from the calculation. To start with Physical component. Hello baber,. For RVUs: Use the License Information. Select CPU and view the Usage % metric. Let me tell you why. 1 Calculate Bandwidth for vSphere Replication. This issue occurs when CPU reservation set on the virtual machine exceeds the physical CPU core capacity for the available ESXi hosts. If you have a 4 vCPU VM and it never exceeds 50% usage then it would be better off with 2 vCPU's. e. 8 vCPUs = 8 cores per socket. from another active cluster - 3 hosts 42 virtual machines. vSphere attempts to keep the VM within a NUMA node until the vCPU count of that VM exceeds the number of physical cores inside a single CPU socket of that particular host. 1. Each logical proc should be treated like any other core. NOTE: At the time of writing the maximum vCPU limit per VM is 36 on i3 instances based on the AWS server hardware capabilities. 1 additional answer. %USED might depend on the frequency with which the CPU core is running. The default parameters used by this tool are for illustration purpose only. Essential Kits, and vSphere Scale Out. Actual processor speed might be higher or lower depending on host power management. You can press capital “ V ” for VM Only view. Otherwise vCD will complain when importing the file that the counters already exist. 6. So if you assign a VM with 1 vCPU to the host, does it: a) use one of the logical processors ( meaning 1 Thread from HT, sharing resources with some other thread that may be using that core) b) use one of the physical cores ( meaning 2 Threads from HT, but only physical core). However, this is not entirely correct, as the vCPU is made up of time slots across all available physical cores, so in general 1vCPU is actually more powerful than a single core, especially if the physical CPUs have 8 cores. You can access information about current. and basing it on purely vCPU then 8 would be minimum but would give little room for moving machines around for patching ESXi, covering off high CPU workloads or providing resilience for potential hardware failures, I would recommend a minimum n+1 so 9 hosts.