Red Hat Enterprise Linux Technology Capabilities and Limits for Retired, Non-Maintained Releases

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 older, retired releases of the operating system that are not currently maintained. For information on more recent versions, please consult the companion knowledgebase article entitled Red Hat Enterprise Linux Technology Capabilities and Limits.

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 3 RHEL 4 RHEL 5
x86 16 32 32
Itanium 2 8 256 [512] 256 [1024]
x86_64 8 64 [64] 160 [255]
POWER 8 64 [128] 128
IBM Z z900: 64 z10 EC: 64 z13: 64

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 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 3 RHEL 4 RHEL 5
x86 64GB1 64GB1 16GB2
Itanium 2 128GB 2TB 2TB
x86_64 128GB 256GB [1TB] 1TB
POWER 64GB 128GB [1TB] 512GB [1TB]
IBM Z z900: 256GB z10 EC: 1.5TB z13: 4TB
Maximum x86 per-process virtual address space Approx. 4GB Approx. 4GB Approx. 3GB2
Maximum x86_64 per-process virtual address space N/A 512GB 2TB
Maximum POWER per-process virtual address space N/A N/A N/A

Minimum required memory

Architecture RHEL 3 RHEL 4 RHEL 5
x86 256MB 256MB 512MB minimum, 1 GB per logical CPU recommended
Itanium 2 512MB 512MB 512MB, 1 GB per logical CPU recommended
x86_64 256MB 256MB 512MB minimum, 1 GB per logical CPU recommended
POWER 512MB 512MB 1GB minimum, 2GB recommended
IBM Z 512MB 512MB 512MB

Minimum required disk space

RHEL 3 RHEL 4 RHEL 5
800MB 800MB 1GB minimum, 5GB recommended

File systems and storage limits

Ext3

Feature RHEL 3 RHEL 4 RHEL 5
Maximum file size 2TB 2TB 2TB
Maximum file system size 2TB 8TB 16TB
Maximum subdirectories 32000 32000 32000
Maximum symlink depth 8 8 8
ACL support Yes Yes Yes

Ext4

Feature RHEL 3 RHEL 4 RHEL 5
Maximum file size -- -- 16TB
Maximum file system size -- -- 16TB [1EB]
Maximum subdirectories -- -- 65000/unlimited
Maximum symlink depth -- -- 8
ACL support -- -- Yes

GFS

Feature RHEL 3 RHEL 4 RHEL 5
Maximum file size 2TB 16TB [8EB] 16TB [8EB]3
Maximum file system size 2TB 16TB [8EB] 16TB [8EB]3
Maximum subdirectories -- unlimited unlimited
Maximum symlink depth -- unlimited unlimited
ACL support -- Yes Yes

GFS2

Feature RHEL 3 RHEL 4 RHEL 5
Maximum file size -- -- 100TB [8EB]
Maximum file system size -- -- 100TB [8EB]
Maximum subdirectories -- -- --
Maximum symlink depth -- -- --
ACL support -- -- --

XFS

Feature RHEL 3 RHEL 4 RHEL 5
Maximum file size -- -- 100TB [8EB]
Maximum file system size -- -- 100TB [16EB]
Maximum subdirectories -- -- unlimited
Maximum symlink depth -- -- 8
ACL support N/A N/A Yes

Storage

Feature RHEL 3 RHEL 4 RHEL 5
Maximum Boot LUN size (BIOS) -- -- 2TB
Maximum Boot LUN size (UEFI) -- -- N/A
Maximum number of device paths (sd devices) 256 256 4 1,024 4,5

Kernel and OS features

Feature RHEL 3 RHEL 4 RHEL 5
Kernel foundation Linux 2.4.21 Linux 2.6.9 Linux 2.6.18
Compiler/toolchain GCC 3.2 GCC 3.4 GCC 4.1
Languages supported 10 15 19
NIAP/CC certified Yes (3+) Yes (4+) Yes (4+)
Common Criteria certified KVM -- -- Evaluated
IPv6 -- -- Ready Logo Phase 2
FIPS certified -- -- Yes (7 modules)
Common Operating Environment (COE) compliant Yes Yes N/A
LSB-compliant Yes - 1.3 Yes - 3 Yes - 3.1
GB18030 No Yes Yes

Client environment

Feature RHEL 3 RHEL 4 RHEL 5
Desktop GUI Gnome 2.2 Gnome 2.8 Gnome 2.16
Graphics XFree86 X.org X.org 7.1.1
OpenOffice v1.1 v1.1.2 v2.0.4 6
GNOME Evolution v1.4 v2.0 v2.8.0
Default browser Mozilla Firefox Firefox 1.5 6

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. 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.
  4. 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.
  5. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
  6. Userspace applications will be updated during the life of the release.

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