Virtualization limits for Red Hat Enterprise Linux with KVM

Updated -

The following limits apply to Red Hat Enterprise Linux Server with KVM virtualization.

For tested limits of OpenShift Virtualization, see the Supported Limits for OpenShift Virtualization 4.x article.

To see limits for the former Red Hat Virtualization product, see Supported limits for Red Hat Virtualization.

Intel 64 and AMD64:

  Red Hat Enterprise Linux 5 Server with KVM Red Hat Enterprise Linux 6 Server with KVM Red Hat Enterprise Linux 7 Server with KVM Red Hat Enterprise Linux 8 Server with KVM Red Hat Enterprise Linux 9 Server with KVM
Maximum number of virtual CPUs in virtualized guest 16 240 240 710 710
Maximum memory in virtualized guest 512 GB1 4 TB1,2,5 6 TB5 16 TB4,5 16 TB4,5
Minimum memory in virtualized guest7 512 MB3 512 MB3 512 MB 512 MB 512 MB

IBM Z:

  Red Hat Enterprise Linux 8 Server with KVM Red Hat Enterprise Linux 9 Server with KVM
Maximum number of virtual CPUs in virtualized guest 2486 2486
Maximum memory in virtualized guest 10 TB5 10 TB5
Minimum memory in virtualized guest7 1.5 GB (2 GB SE)8 1.5 GB (2 GB SE)8

64-bit ARM:

  Red Hat Enterprise Linux 9 Server with KVM
Maximum number of virtual CPUs in virtualized guest 384
Maximum memory in virtualized guest 1 TB
Minimum memory in virtualized guest7 1.5 GB

IBM POWER 8 and POWER 9:

  Red Hat Enterprise Linux 7 Server with KVM Red Hat Enterprise Linux 8 Server with KVM Red Hat Enterprise Linux 9 Server with KVM
Maximum number of virtual CPUs in virtualized guest 192 384 Unsupported
Maximum memory in virtualized guest 10 TB5 10 TB5 Unsupported
Minimum memory in virtualized guest7 2 GB 2 GB Unsupported

Other support considerations:

  • Supported limits reflect the current state of system testing by Red Hat and its partners. Systems exceeding these supported limits may be included in the Hardware Catalog after joint testing between Red Hat and its partners. If they exceed the supported limits posted here, entries in the Hardware Catalog will be fully supported.
  • In addition to supported limits reflecting hardware capability, there may be additional limits under the Red Hat Enterprise Linux subscription terms. Supported limits are subject to change based on ongoing testing activities.
  • For limits using the Xen hypervisor included with Red Hat Enterprise Linux 5, see Virtualization limits for Red Hat Enterprise Linux with Xen
  • Until 2021 there was a support limit of 4 active guests per RHEL hypervisor. This limit has been removed so more than 4 guests are supported.

Footnotes:

  1. Supports the maximum supported memory in the host, all of which may be allocated to the virtualized guest. 32-bit guests with Physical Address Extension (PAE) support will only be able to access 64 GB. This is a virtual hardware limitation.
  2. For Red Hat Enterprise Linux 6.2 and earlier, the maximum memory in a virtual machine is 512 GB. For Red Hat Enterprise Linux 6.3, the maximum memory in a virtual machine is 2000 GB.
  3. This is the recommended limit in text mode. The graphical mode requires 640 MB.
  4. Note that virtualized guests larger than 8 TB currently require explicit virtual NUMA configuration, because the maximum virtual NUMA node size is 8 TB.
  5. Live migrating guests with more than 1 TB of memory may have certain limitations. For details see the RHEL 8 or RHEL 9 documentation, based on your version of RHEL.
  6. If the VM is running in secure execution mode, the vCPU limit on IBM Z is only 247.
  7. VMs with only the minimum required memory are not suitable for running a more extensive configuration, such as a high number of virtual CPUs or devices.
  8. If the VM is running in secure execution mode, it requires more RAM to function correctly.
  • Component
  • kvm

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