Red Hat Enterprise Linux Technology Capabilities and Limits

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What can Red Hat® Enterprise Linux® do? Find out in this chart of the supported and theoretical limits of the platform.

This article provides information for releases of the operating system that are currently maintained. For information on older, retired releases that are no longer maintained, please consult the companion knowledgebase article entitled Red Hat Enterprise Linux Technology Capabilities and Limits for Retired, Non-Maintained Releases.

Supported limits reflect the current state of system testing by Red Hat and its partners for mainstream hardware. 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 include a reference to the details of the system-specific limits and 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 as ongoing testing completes.

The following values are formatted as tested and supported [theoretical].

Maximum logical CPUs

Red Hat defines a logical CPU as any schedulable entity. So every core/thread in a multicore/thread processor is a logical CPU.

Architecture RHEL 6 RHEL 7 RHEL 8 RHEL 9
x86 32 N/A1 N/A1 N/A1
x86_64 448 [4096]2 768 [5120]3 768 [8192] 1792 [8192]
Power 128 768 [2048]4 POWER8: 768 [2048]
POWER9: 1536 [2048]5
Power10: 1920 [2048]6		 POWER9: 1536 [2048]
Power10: 1920 [2048]19
IBM Z z13: 64 z13: 256 z13: 256
z14: 340
z15: 380
z16: 400		 z14: 340
z15: 380
z16: 400
ARM N/A N/A 256 512 [4096]

Maximum memory

The architectural limits are based on the capabilities of the Red Hat Enterprise Linux kernel and the physical hardware. Red Hat Enterprise Linux 6 limit is based on 46-bit physical memory addressing. Red Hat Enterprise Linux 5 limit is based on 40-bit physical memory addressing. All system memory should be balanced across NUMA nodes in a NUMA-capable system.

Architecture RHEL 6 RHEL 7 RHEL 8 RHEL 9
x86 16GB N/A1 N/A1 N/A1
x86_64 12TB [64TB]7 12TB [64TB]8 24TB [64TB] 48TB [64TB]
Power 2TB 32TB9 POWER8: 32TB [128TB]
POWER9: 64TB [128TB]10
Power10: 64TB [128TB]11		 POWER9: 64TB [128TB]
Power10: 64TB [128TB]11
IBM Z z13: 4TB z13: 10TB z13: 10TB
z14: 16TB
z15: 16TB
z16: 32TB		 z14: 16TB
z15: 16TB
z16: 32TB
ARM N/A N/A 1.5TB [256TB] 1.5TB [256TB]
Maximum x86 per-process virtual address space Approx. 3GB N/A1 N/A1 N/A1
Maximum x86_64 per-process virtual address space 128TB 128TB 128TB 128TB
Maximum Power per-process virtual address space -- -- 4PB12 4PB12

Minimum required memory

Architecture RHEL 6 RHEL 7 RHEL 8 RHEL 9
x86 512MB minimum, 1 GB per logical CPU recommended N/A1 N/A1 N/A1
x86_64 1GB minimum, 1 GB per logical CPU recommended 1GB minimum, 1 GB per logical CPU recommended13 1.5 GiB for local media or NFS network installation, 3 GiB for HTTP(S) and FTP network installation 1.5 GiB for local media or NFS network installation, 3 GiB for HTTP(S) and FTP network installation
Power 2GB minimum, 2GB required per install 2GB minimum, 2GB required per install 3 GiB for local media or NFS network installation, 4 GiB for HTTP(S) and FTP network installation 3 GiB for local media or NFS network installation, 4 GiB for HTTP(S) and FTP network installation
IBM Z 512MB 1GB 1.5 GiB for local media or NFS network installation, 3 GiB for HTTP(S) and FTP network installation 1.5 GiB for local media or NFS network installation, 3 GiB for HTTP(S) and FTP network installation
ARM N/A N/A 1.5 GiB for local media or NFS network installation, 4 GiB for HTTP(S) and FTP network installation 1.5 GiB for local media or NFS network installation, 4 GiB for HTTP(S) and FTP network installation

Minimum required disk space

RHEL 6 RHEL 7 RHEL 8 RHEL 9
1GB minimum, 5GB recommended 10GB minimum, 20GB recommended 10GB minimum, 20GB recommended 10GB minimum, 20GB recommended

File systems and storage limits

Ext3

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Maximum file size 2TB 2TB 2TB 2TB
Maximum file system size 16TB 16TB 16TB 16TB
Maximum subdirectories 32000 32000 32000 32000
Maximum symlink depth 8 8 8 8
ACL support Yes Yes Yes Yes

Ext4

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Maximum file size 16TB 16TB 16TB 16TB
Maximum file system size 16TB [1EB] 50TB [1EB] 50TB [1EB] 50TB [1EB]
Maximum subdirectories 65000/unlimited 65000/unlimited 65000/unlimited 65000/unlimited
Maximum symlink depth 8 8 8 8
ACL support Yes Yes Yes Yes

GFS

Please see the knowledgebase article entitled Red Hat Enterprise Linux Technology Capabilities and Limits for Retired, Non-Maintained Releases for information about GFS support.

GFS2

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Maximum file size 100TB [8EB] 100TB [8EB] 100TB [8EB] 100TB [8EB]
Maximum file system size 100TB [8EB] 100TB [8EB] 100TB [8EB] 100TB [8EB]
Maximum subdirectories unlimited unlimited unlimited unlimited
Maximum symlink depth unlimited unlimited unlimited unlimited
ACL support Yes Yes Yes Yes

XFS

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Maximum file size 100TB [8EB] 500TB [8EB] 8EB 8EB
Maximum file system size 300TB [16EB]14 500TB [16EB] 1PB 1PB
Maximum subdirectories unlimited unlimited unlimited unlimited
Maximum symlink depth 8 8 8 8
ACL support Yes Yes Yes Yes

Storage

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Maximum Boot LUN size (BIOS) 2TB15 2TB15 2TB 2TB
Maximum Boot LUN size (UEFI) 32bit (i686) - 2TB,
64bit - 16TB (tested limit)		 50TB 8EB 8EB
Maximum number of device paths (sd devices) 8,192 16,17 10,000 16,17 10,000 16,17 10,000 16,17

Kernel and OS features

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Kernel foundation 2.6.32 - 2.6.34 3.10 4.18 5.14
Compiler/toolchain GCC 4.4 GCC 4.8.2 GCC 8.2.1 GCC 11.2.1
Languages supported 22 22 TBD TBD

Certifications and Standards

Many government certifications and standards including Common Criteria, FIPS 140-2 / 140-3, IPv6, and CJIS are now listed on our Government Standards page.

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Common Operating Environment (COE) compliant N/A N/A Under Discussion Under Discussion
LSB-compliant Yes - 4.0 Under Evaluation (4.1) Under Discussion Under Discussion
GB18030 Yes Yes Yes Yes

Client environment

Feature RHEL 6 RHEL 7 RHEL 8 RHEL 9
Desktop GUI Gnome 2.28 Gnome 3.8 Gnome 3.2818 Gnome 40, plus updates18
Graphics X.org 7.4 X.org 7.7 Wayland 1.1518 Wayland 1.1918
Office suite OpenOffice v3.2 18 LibreOffice v4.1.4 18 LibreOffice v6.0.6.118 LibreOffice v7.1.8.118
GNOME Evolution v2.28 v3.8.5 v3.28.518 v3.40.418
Default browser Firefox 3.6 18 Firefox 24.5 18 Firefox 60.5.118 Firefox 91.8.018

Notes

  1. Red Hat Enterprise Linux 7 and newer releases do not include support for the 32-bit x86 architecture.
  2. Red Hat Enterprise Linux 6.7 or newer is required for 448 CPU support. The previous maximum supported CPU count for earlier versions was 288 CPUs.
  3. Red Hat Enterprise Linux 7.3 with errata kernel 3.10.0-514.26.2.el7 or newer is required for 768 CPU support. Red Hat Enterprise Linux 7.2 with errata kernel 3.10.0-327.18.2.el7 or newer is required for 576 CPU support. Red Hat Enterprise Linux 7.2 or newer is required for 384 CPU support. The previous maximum supported CPU count for earlier versions was 288 CPUs. Also, for 7.2 or newer, please refer to the following Red Hat Knowledgebase article: Memory swap occurs while the pagecache is reclaimed.
  4. Red Hat Enterprise Linux 7.5 or newer, Red Hat Enterprise Linux 7.4 Extended Update Support (EUS) kernel version 3.10.0-693.25.2.el7 or newer, or Red Hat Enterprise Linux 7.3 Extended Update Support (EUS) kernel version 3.10.0-514.48.1.el7 or newer is required for 768 CPU support. The previous maximum supported CPU count for earlier update releases or EUS kernels of Red Hat Enterprise Linux 7 was 192 CPUs.
  5. Red Hat Enterprise Linux 8.2 or newer is required to support 1536 CPUs on IBM POWER9 systems. The maximum supported CPU count on Red Hat Enterprise Linux 8.0 and 8.1 for POWER9 is 768 CPUs.
  6. Initial testing demonstrated full support for 1536 CPUs on IBM Power10 systems running Red Hat Enterprise Linux 8.4 or newer. Further testing has allowed us to raise the maximum supported CPU count to 1920 CPUs when running Red Hat Enterprise Linux 8.4 or newer on IBM Power10 systems.
  7. Red Hat Enterprise Linux 6.7 is required for support of 12TB of RAM. Red Hat Enterprise Linux 6.6 can support up to 6TB of RAM. Previous versions of Red Hat Enterprise Linux 6, starting with Red Hat Enterprise Linux 6.3, support up to 3TB of RAM. Versions of Red Hat Enterprise Linux prior to Red Hat Enterprise Linux 6.3 support up to 1TB of RAM.
  8. Red Hat Enterprise Linux 7.2 is required for support of 12TB of RAM. Red Hat Enterprise Linux 7.1 can support up to 6TB of RAM. Previous versions of Red Hat Enterprise Linux 7 (i.e. Red Hat Enterprise Linux 7.0) support up to 3TB of RAM. Red Hat Enterprise Linux 7.2 is required for support of 12TB of RAM. Red Hat Enterprise Linux 7.1 can support up to 6TB of RAM. Previous versions of Red Hat Enterprise Linux 7 (i.e. Red Hat Enterprise Linux 7.0) support up to 3TB of RAM.
  9. Red Hat Enterprise Linux 7.5 or newer, Red Hat Enterprise Linux 7.4 Extended Update Support (EUS) kernel version 3.10.0-693.25.2.el7 or newer, or Red Hat Enterprise Linux 7.3 Extended Update Support (EUS) kernel version 3.10.0-514.48.1.el7 or newer is required for support of 32TB of RAM. Previous update releases or EUS kernels of Red Hat Enterprise Linux 7 could support up to 2TB of RAM.
  10. Red Hat Enterprise Linux 8.2 or newer is required to support 64TB of RAM on IBM POWER9 systems. The maximum supported amount of RAM on Red Hat Enterprise Linux 8.0 and 8.1 for POWER9 is 32TB.
  11. Red Hat Enterprise Linux 8.6 or newer, or Red Hat Enterprise Linux 9.2 or newer is required to support 64TB of RAM on IBM Power10 systems. The maximum supported amount of RAM on Red Hat Enterprise Linux 8.4 and 8.5 for IBM Power10 systems is 32TB, and the maximum supported amount of RAM on Red Hat Enterprise Linux 9.0 and 9.1 for IBM Power10 systems is 32TB.
  12. For processors supporting 52-bit virtual addressing.
  13. Red Hat Enterprise Linux 7 Network / PXE install requires at least 1.5 GB of RAM for the install procedure only.
  14. Red Hat Enterprise Linux 6.8 or newer is required for 300TB XFS filesystem support on RHEL 6.x. The previous maximum supported XFS filesystem size in RHEL 6.7 and earlier was 100TB.
  15. UEFI and GPT support are required for more that 2TB boot LUN support as detailed in the Knowledgebase article entitled Boot drive requirements for Red Hat Enterprise Linux .
  16. Larger numbers are possible, depending on testing and support by the specific hardware vendor. Consult your hardware vendor to determine their limit, and confirm with your Red Hat support representative. In no case will Red Hat support a limit that exceeds the limit supported by the hardware vendor.
  17. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
  18. Userspace applications will be updated during the life of the release.
  19. Initial testing demonstrated full support for 1536 CPUs on IBM Power10 systems running Red Hat Enterprise Linux 9.0 or newer. Further testing has allowed us to raise the maximum supported CPU count to 1920 CPUs when running Red Hat Enterprise Linux 9.0 or newer on IBM Power10 systems.

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