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
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.
The x86 Hugemem kernel is not provided in Red Hat Enterprise Linux 5 or newer releases.
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.
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.
It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
Userspace applications will be updated during the life of the release.