6.5.1

Table Of Contents
You can configure a virtual machine that runs on an ESXi host 6.0 and later to have up to 128 virtual
CPUs. A virtual machine cannot have more virtual CPUs than the actual number of logical CPUs on the
host. The number of logical CPUs means the number of physical processor cores or two times that
number if hyperthreading is enabled. For example, if a host has 128 logical CPUs, you can configure the
virtual machine for 128 virtual CPUs.
You configure how the virtual CPUs are assigned in terms of cores and cores per socket. Determine how
many CPU cores you want in the virtual machine, then select the number of cores you want in each
socket, depending on whether you want a single core CPU, dual-core CPU, tri-core CPU, and so on. Your
selection determines the number of sockets that the virtual machine has.
For more information about multicore CPUs, see the vSphere Resource Management documentation.
Change CPU Hot Plug Settings
By default, you cannot add CPU resources to a virtual machine when the virtual machine is turned on.
The CPU hot plug option lets you add CPU resources to a running virtual machine.
The following conditions apply:
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For best results, use virtual machines that are compatible with ESXi 5.0 or later.
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Hot-adding multicore virtual CPUs is supported only with virtual machines that are compatible with
ESXi 5.0 or later.
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Not all guest operating systems support CPU hot add. You can disable these settings if the guest is
not supported.
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To use the CPU hot plug feature with virtual machines that are compatible with ESXi 4.x and later, set
the Number of cores per socket to 1.
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Adding CPU resources to a running virtual machine with CPU hot plug enabled disconnects and
reconnects all USB passthrough devices that are connected to that virtual machine.
Prerequisites
Required privileges: Virtual Machine.Configuration.Settings
Verify that the virtual machine is running and is configured as follows.
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Latest version of VMware Tools installed.
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Guest operating system that supports CPU hot plug.
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Virtual machine compatibility is ESX/ESXi 4.x or later.
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Virtual machine is turned off.
Procedure
1 Right-click a virtual machine in the inventory and select Edit Settings.
2 On the Virtual Hardware tab, expand CPU, and select Enable CPU Hot Add.
3 Click OK.
vSphere Virtual Machine Administration
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