Supported Limits for Red Hat Virtualization

Updated -

Introduction

These maximums and minimums are based on performance testing of Red Hat Virtualization (RHV) 4.x and Red Hat Enterprise Virtualization (RHEV) 3.x. as a large-scale environment.

To operate Red Hat Virtualization as a large-scale environment, apply the recommendations in Guidelines for Large Deployments of Red Hat Virtualization.

Red Hat Virtualization 4.x Limits

The following limits apply to Red Hat Virtualization (RHV) 4.x

Virtual Machine Maximums:

  • Maximum concurrently running virtual machines: Unlimited
  • Maximum virtual CPUs per virtual machine:
    • 288 for RHV 4.0-4.1
    • 384 for RHV 4.2-4.3
  • Maximum memory per virtual machine: 4 TB1
  • Minimum memory per virtual machine: N/A
  • Maximum single disk size per virtual machine: 8 TB

1. Supports the maximum memory per VM in the host, all of you can allocate to the virtual machine. 32-bit guests with Physical Address Extension (PAE) support are only able to access 64 GB. This is a virtual hardware limitation.

Host Maximums:

The following maximums apply to the Red Hat Virtualization Host (RHVH) and Red Hat Enterprise Linux host.

  • Logical CPU cores or threads: 768
  • RAM: 12 TB
  • Number of hosted virtual machines: 250
  • Simultaneous live migrations: 2 incoming, 2 outgoing (more)
  • Live migration bandwidth: Default to 52 MiB (~436 Mb) per migration when using the legacy migration policy. Other policies use adaptive throughput values based on the speed of the physical device. QoS policies can limit migration bandwidth.

Self-hosted Engine (SHE) Maximums:

  • Number of nodes per cluster: 7

RHV Manager Logical Entity Maximums:

  • Data center
    • Maximum data center count: 400
    • Maximum host count: 400 supported, 500 tested
    • Maximum VM count: 4000 supported, 5000 tested
  • Cluster
    • Maximum cluster count: 400
    • Maximum host count: 400 supported, 500 tested
    • Maximum VM count: 4000 supported, 5000 tested
  • Network
    • Logical networks/cluster: 300
    • SDN/external networks: 2600 tested, no enforced limit
  • Storage
    • Maximum domains: 50 supported, 70 tested
    • Hosts per domain: No limit
    • Logical volumes per block domain (more): 1500
    • Maximum number of LUNs (more): 300
    • Maximum disk size: 500 TiB (limited to 8 TiB by default)

Other:

  • SPM - Concurrent activities (metadata operations, storage live migration, etc.): 10

Red Hat Enterprise Virtualization 3.x

NOTE More detailed maximums for RHEV 3.x are not available.

  • Maximum number of concurrently running virtual machines: Unlimited
  • Maximum number of virtual CPUs per virtual machine: 160
  • Maximum memory per virtual machine: 2 TB1
  • Minimum memory per virtual machine: 512 MB

1. Supports the maximum memory per VM in the host, all of you can allocate to the virtual machine. 32-bit guests with Physical Address Extension (PAE) support are only able to access 64 GB. This is a virtual hardware limitation.

Notes

The following notes apply to all versions of Red Hat Virtualization.

  • 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 are 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.
  • These limits do not apply to Red Hat Enterprise Linux (RHEL) with KVM virtualization, which offers virtualization for low-density environments. Instead, see "Virtualization limits for RHEL with KVM".
  • Guest operating systems have different minimum memory requirements. Virtual machine memory can be allocated as small as required.
  • More specific limitations can be found in the "Requirements" topic of the RHV "Planning and Prerequisites Guide: Requirements."

RHV 4.x

RHV 4.3

RHV 4.2

RHV 4.1

RHV 4.0

RHV 3.x

9 Comments

Can this article be improved (or another article created) to provide documentation around the physical maximums? For example, how many hosts per cluster are supported? How many clusters per datacenter? How many CPU / host? How much RAM / host? How many LUNS (FC/iSCSI) per host?

Hi John
Many of those limits are reported in the Technical Guide, for example, for 3.5 you can find it at https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.5/html-single/Technical_Guide/index.html#Minimum_requirements_and_supported_limits

Where it lists limits of ram, storage, etc.

Hi ,
I think this is not correct documentation --> "A maximum of 2 TB of RAM is supported."

Saludos
Roberto D.

Please update this KB with the RHEV 4 Limits.

Please update this KB with the RHEV 4 Limits.

There is a new document for RHV 4.1 with comprehensive information: Red Hat Virtualization Manager Limitations At the moment when I am writing it is still not finished but RH is conducting very thorough performance/limitation tests. When they finish, it will be the most accurate and precise document.

max vCPUs is not accurate. RHV 4.2 has a limit of 288, and 4.2-4.3 has 384

Hi Michal,

There is a typo: RHV 4.1 has a limit of 288, and RHV 4.2-4.3 has 384, right?

For the RHV 4.x Manager Storage Limits: I would guess the limits of storage domain are per datacenter (otherwise it would not make sense to have 400 datacenters). Same goes for the Maximum number of LUNs, I guess that's per storage domain and not a global limit as stated currently.

Additional question: how do direct LUNs behave? Is there a limit on those?