Red Hat Enterprise Linux Technology Capabilities and Limits

Updated -

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 For information on older, retired releases that are no longer maintained, please consult the companion knowledgebase article entitled Red Hat Enterprise Linux Technology Capabilities and Limits for Retired, Non-Maintained Releases.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: 1536 [2048]
IBM Z z13: 64 z13: 256 z13: 256
z14: 340
z14: 340
z15: 380
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: 32TB [128TB]11
POWER9: 64TB [128TB]
Power10: 32TB [128TB]
IBM Z z13: 4TB z13: 10TB z13: 10TB
z14: 16TB
z14: 16TB
z15: 16TB
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 8.4 or newer is required to support 32TB of RAM on IBM Power10 systems.
  12. For processors supporting 52-bit virtual addressing.
  13. 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.

69 Comments

Very helpful information.

Very well done, indeed!

  1. Officially support 125 CPUs across the entire machine. -> to what item does this note apply?

Excellent and very useful information .

Thanks for your useful information.

May I ask what is this mean?

Maximum logical CPUs 
Specification   Version 3   Version 4   Version 5   Version 6        Version 7
x86_64                 8      64 [64]   160 [255]   240 [4096]        240 [5120]

For example, why the limit has two part of number? first 240 and second [5120]?
can you help me to understand, what is the [5120] mean?

thanks..

Hello Justin,

The first number is the tested limit, which is the maximum quantity that Red Hat's engineering and technical support teams have verified as fully functional for a given parameter. Certified systems are expected to behave correctly up to that limit. The second number is the theoretical limit, the maximum value the kernel and userspace, if applicable, should be able to support based on the current source code.

Hi,
Currently i'm using 30 days trial subscription for RHEL 6.6.
Server configuration: 2 x Xeon 6 core processor (with threading), 32 GB RAM.
Server carried high amount of network traffic, but server not take more than 55% CPU load.
I found that some CPUs are more than 80% free only 3 CPUs are 95% used.
Is trial subscription limits CPU usages/utilization?

Thanks.

Hello Rashed,
RHEL 6.6 eval subscription has no such CPU usages limitation. I suppose you should check network or your applications relevant issue or If you want to test 100% all CPU utilization on RHEL 6.6 then you can run multiple session of dd command or some other commands to generate CPU dummy load. Before this you should also ensure that the server hardware is certified with RHEL 6.6. You can use the following URL for hardware certification check on RHEL 6.
https://hardware.redhat.com/RHEL6

Best Regards
Deepak

Hi Deepak,
Thanks for your replay.
We found an issue with IRQ settings, we have changed IRQ & RPS settings & now its ok.
Thanks.

-Rashed

Thanks for the useful information

Which is the maximum LUN and physical volume size for RHEL 6 64bit?

From the point of view of the operating system, every path to a LUN is a separate device. As a result, we specify the max. number of paths that are supported (for example, 8,192 in RHEL 6). The number of LUNs will depend on the number of paths to those LUNs.

For the purpose of specifying the max. physical volume size, we use the largest supported filesystem size (100TB for RHEL 6). Although it is possible for a physical volume to have multiple filesystems (or logical volumes) on it, and the theoretical max. volume size is much larger, this limit is based on the largest volume we are able to test.

Very helpful information.

It is worth noting that minimum required RAM for normal installation via Anaconda for RHEL7 is 1 GiB but if you select all packages this can be as big as 1.5 GiB.

This seems be failing with 1 GiB with @base on RHEL 7.3 via Anaconda. I think we should change this to be at least 1.5 GiB for the RAM requirement. The same kickstart file worked fine under RHEL 7.2 with the memory at 1 GiB.

Anaconda in RHEL 8.1 seems to have even more demands when installing EFI system via Kickstart. I had to bump the memory to 3GB in order for the installation to proceed, otherwise I saw the famous "Pane is dead" error.

Ah i missed this comment originally. This makes me feel better it is not just me. 3GB for BIOS or EFI kickstarts is now required (closer to 2.5 GB really)

Well done fellas.

Missing the ACL limit for each filesystem

very helpful indeed.

The first row X86 Maximum logical CPUs it is listed as N/A with a note 6 note 6 talks about memory? looks like it should be note 8 8. Officially support 125 CPUs across the entire machine. this note talks about CPUs I cannot find anything on the list that has note 8 listed for note information

Actually, that note is saying that the memory number is N/A because those versions do not have a 32-bit x86 or Itanium2 version.

we are purchased the intel i3/i5 7th processor Dell/HP desktop systems, So, Im trying to install Redhat 6.5/7.4 but is is showing un supported hardware and is not entering into installation mode. kindly suggest solution

Greetings,

All certified hardware is listed in the Red hat Hardware catalog: https://hardware.redhat.com/RHEL

Please search the catalog to locate the model of interest. If it's not listed, then it may not have been certified by your favorite vendor. You can also cross reference the RHEL certification with the vendor's support website.

HTH

Ron

Red Hat Enterprise Linux 7.5+ requires 1.5 GiB as minimum amount of RAM for HTTP, HTTPS, or FTP network installation as per: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/installation_guide/sect-installation-planning-disk-space-memory-x86

I'm sorry if this is in the wrong section but I'm having trouble installing RHEL7.5 on an Intel i7-8750H (Hexa Core) processsor. Can someone please point me to a list that shows the supported processor listing?

@PA - To specific targeted hardware, you can have a try here : https://catalog.redhat.com/hardware/components/search

If more global (complete server or a workstation for instance ) : https://catalog.redhat.com/hardware/servers/search https://catalog.redhat.com/hardware/workstations/search

All hardware : https://catalog.redhat.com/hardware

It is very helpful. Thank you.

Comprehensive!

Very helpful in order to know the capability and limits of redhat os

helpful and easy to ready/format.

very useful information

Good Work guys, keep it up

Helpful!!! ... Thank's

Awesome! Happy to have found this.

Important and Valuable information.

Please note that a more up-to-date list of Common Criteria, FIPS and other government certification standards is available at the following Customer Access Portal site : Government Standards

It does look like working at the moments.

I believe the XFS table has a typo in it: for RHEL 8, it lists the "Maximum file size" as 8EB (approximately 8*10^18 bytes), and the "Maximum file system size" as only 1PB (approximately 1*10^15 bytes). Should these values be swapped?

Additionally, it has only these numbers, without a separate theoretical limit. What has RHEL 8 been tested to, and what is its theoretical limit? If only the theoretical limit is available, it would be helpful to denote this in the table, either by enclosing the values in brackets, by adding a footnote, or both.

Edit: Reformatted to display asterisks

Hi Joshua -

The file size vs file system size numbers are correct. The file size here refers to maximum file offset, not actual space consumed, i.e. an 8EB sparse file is quite possible on a 1PB filesystem. A footnote would be helpful here to avoid confusion..

The 8EB file size / 1PB filesystem size numbers are the RHEL8 tested limits. Theoretical limits remain the same as prior versions (8EB file size, 16EB filesystem size.) I'll get the theoretical limits added on the RHEL8 column.

(As an aside, simple statements of these theoretical sizes for filesystems can be tricky; in reality, these maximums tend to depend on fs block size, and in turn on system page size, but that level of detail can be difficult to provide in a table like this.)

Thanks, -Eric

The limits quoted here are tested limits, and that defines the limits of our support. In some cases those coincide with theoretical limits. Both the maximum file size and maximum file system size are stated correctly. You would need a sparse file in order to approach the maximum file size limit, of course, since the maximum file system size is smaller. We could add theoretical limits, but I'm not sure that is useful, if it comes without support and might even be confusing. If you need a larger limit than those stated here, it would be best to open a support case and request it. We are always happy to provide advice and understanding requirements from customers helps us set the limits for our testing and support.

Well done was very good at that moment, Thanks so much.

cool

Can Redhat run on AMD processors like TR4?

I will try the mighty RHEL in a web server. Thanks for the information

thank you for the information

Thank you for the information

It's so nice!

It's so nice!

It's so nice information, thanks

It's so nice information, thanks

Hi Gals and Guys, It seems to have a mistake on the XFS tab except my mistake.

XFS Feature RHEL 3 RHEL 4 RHEL 5 RHEL 6 RHEL 7 RHEL 8 Maximum file size -- -- 100TB [8EB] 100TB [8EB] 500TB [8EB] 8EB Maximum file system size -- -- 100TB [16EB] 300TB [16EB]15 500TB [16EB] 1PB

The max file system size can't be inferior to a max file. So How can we have 8EB for a file when a FS could reach only 1PB ?

8 EB > 1 PB right ?

Regards, AM

Those limits are correct. The reason that a file can be larger than the filesystem is that files can be sparse, so they don't need backing with blocks on the filesystem in that case. You can easily test this out by using (for example) the truncate(1) utility to create a file larger than the filesystem. If you stat(1) the file, you can then see that it takes up a very small amount of disk space, but has a much larger file size.

The limits on the filesystem size here are based on what we are able to test. So these limits are support limits and not theoretical maximum limits. I hope that makes it a bit clearer. Let us know if you have any more questions.

Well presented info. Thanks!

looking forward to enhancing my skills with RHEL 8.5

I can see that one of the storage capabilities limit objects is 'Boot LUN size', but how about the non-boot lun size?

Thank you.

Useful info.

Very useful and informative article, added it to my bookmarks. Also found another page link is useful https://access.redhat.com/articles/rhel-kvm-limits.

I think its unfortunate following the link from Rhel 8 preface to see nearly the whole Kernel and OS feature section of Rhel 8 and 9 being under discussion or TBD. Aside this the rest is useful.

Are we sure the PXE comment is still accurate? 'Network / PXE install requires at least 1.5 GB of RAM for the install procedure only.'

I am trying to install RHEL8 using PXE on a system with 2GB and it fails with "Write error, no space left on device". The 4GB HW works just fine.

Well to probably answer my own question this document just appears wrong. The boot image in RHEL8.6 is 2.5GB in size. Unless there is some way to reduce that, the minimum size is > 2.5 GB RAM

Just to continue my self conversation, I further proved this out. I modified the provided squashfs.img file in RHEL8 and removed files I didn't need. Once I got the file down to 2GB, the installation worked without a hitch.

When this occurred were you doing a PXE/NFS install or a PXE/HTTP install?

As noted in the install guide NFS installs require 1.5GiB but HTTP/HTTPS/FTP installs require 3GiB.

This document just says "Network / PXE install requires at least 1.5 GB of RAM for the install procedure only."

There is no mention of NFS or HTTP that I see (not saying there aren't other documents that contradict this, just that this appears wrong).

Seems weird that it would matter. Unless in NFS it mounts the squashfs, which i guess is possible. I'd have to try that

I tried a NFS install and it appears to also require 3GB as best I can tell.

Looks like RHEL confirmed the requirement is indeed now 3GB in RHEL8, they are working on updating all the documentation.