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

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/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.

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.

Minimum required memory

Minimum required disk space

File systems and storage limits

Ext3

Ext4

GFS

GFS2

XFS

Storage

Kernel and OS features

Client environment

Notes

1. The SMP kernel supports a maximum of 16GB of main memory. Systems with more than 16GB of main memory use the Hugemem kernel. In certain workload scenarios it may be advantageous to use the Hugemem kernel on systems with more than 12GB of main memory.
2. The x86 Hugemem kernel is not provided in Red Hat Enterprise Linux 5 or newer releases.
3. Red Hat Enterprise Linux 6 and newer releases do not include support for the Itanium 2 architecture. Red Hat Enterprise Linux 7 and newer releases do not include support for the 32-bit x86 architecture.
4. If there are any 32-bit machines in the cluster, the maximum gfs file system size is 16TB. If all machines in the cluster are 64-bit, the maximum size is 8EB.
5. Officially support 125 CPUs across the entire machine.
6. Requires Intel EPT and AMD RVI technology support.
7. UEFI and GPT support required for more that 2TB boot LUN support: https://access.redhat.com/kb/docs/DOC-16981.
8. Userspace applications will be updated during the life of the release.
9. 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.
10. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
11. 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.
12. 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.
13. 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.
14. 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.
15. 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.
16. 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.
17. 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.
18. Network / PXE install requires at least 1.5 GB of RAM for the install procedure only.
19. For processors supporting 52-bit virtual addressing.