ClearOS Technology Capabilities and Limits

This article provides the supported and theoretical limits of ClearOS®.

What can ClearOS® do? Find out in this quick-glance chart of the supported and theoretical 1 limits of the platform.

Specification Version 3 Version 4 Version 5 Version 6 Version 7
Maximum logical CPUs 2
x86 16 32 32 32 N/A6
Itanium 2 8 256 [512] 256 [1024] N/A6 N/A6
x86_64 8 64 [64] 160 [255] 288 [4096]17 288 [5120]17
POWER 8 64 [128] 128 128 192 [2048]
System z 64 (z900) 64 (z10 EC) 64 (z13) 64 (z13) 256 (z13)
Maximum memory5
x86 64GB3 64GB3 16GB4 16GB4 N/A6
Itanium 2 128GB 2TB 2TB N/A6 N/A6
x86_64 128GB 256GB [1TB] 1TB 12TB [64TB]15 12TB [64TB]16
POWER 64GB 128GB [1TB] 512GB [1TB] 2TB 2TB
System z 256GB (z900) 1.5TB (z10 EC) 4TB (z13) 4TB (z13) 10TB (z13)
Maximum number of device paths ("sd" devices)
256 256 13 1,024 13,14 8,192 13,14 10,000 13,14
Required minimums
x86 256MB 256MB 512MB minimum/1 GB per logical CPU recommended 512MB minimum/1 GB per logical CPU recommended N/A6
x86_64 256MB 256MB 512MB minimum/1 GB per logical CPU recommended 1GB minimum/1 GB per logical CPU recommended 1GB minimum/1 GB per logical CPU recommended
Itanium 2 512MB 512MB 512MB/1 GB per logical CPU recommended N/A6 N/A6
POWER 512MB 512MB 1GB minimum/2GB recommended 2GB minimum/2GB required per install 2GB minimum/2GB required per install
Minimum diskspace 800MB 800MB 1GB minimum/5GB recommended 1GB minimum/5GB recommended 10GB minimum/20GB recommended
File systems and storage limits
Ext3 - Maximum file size 2TB 2TB 2TB 2TB 2TB
Ext3 - Maximum file system size 2TB 8TB 16TB 16TB 16TB
Ext3 - Maximum subdirectories 32000 32000 32000 32000 32000
Ext3 - Maximum symlink depth 8 8 8 8 8
Ext3 - ACL support Yes Yes Yes Yes Yes
Ext4 - Maximum file size -- -- 16TB 16TB 16TB
Ext4 - Maximum file system size -- -- 16TB [1EB] 16TB [1EB] 50TB [1EB]
Ext4 - Maximum subdirectories -- -- 65000/unlimited 65000/unlimited 65000/unlimited
Ext4 - Maximum symlink depth -- -- 8 8 8
Ext4 - ACL support -- -- Yes Yes Yes
GFS - Maximum file size 2TB 16TB [8EB] 16TB [8EB]7 N/A N/A
GFS - Maximum file system size 2TB 16TB [8EB] 16TB [8EB]7 N/A N/A
GFS2 - Maximum file size -- -- 100TB [8EB] 100TB [8EB] 100TB [8EB]
GFS2 - Maximum file system size -- -- 100TB [8EB] 100TB [8EB] 100TB [8EB]
XFS - Maximum file size -- -- 100TB [8EB] 100TB [8EB] 500TB [8EB]
XFS - Maximum file system size -- -- 100TB [16EB] 300TB [16EB]18 500TB [16EB]
XFS - Maximum subdirectories -- -- unlimited unlimited unlimited
XFS - Maximum symlink depth -- -- 8 8 8
XFS - ACL support N/A N/A Yes Yes Yes
Maximum Boot LUN size (BIOS) -- -- 2TB 2TB10 2TB10
Maximum Boot LUN size (UEFI) -- -- N/A 32bit (i686) - 2TB,
64bit - 16TB (tested limit)
50TB
Maximum x86 per-process virtual address space Approx. 4GB Approx. 4GB Approx. 3GB4 Approx. 3GB4 N/A6
Maximum x86_64 per-process virtual address space 512GB 2TB 128TB 128TB
Kernel and OS features
Kernel foundation Linux 2.4.21 Linux 2.6.9 Linux 2.6.18 2.6.32 - 2.6.34 3.10
Compiler/toolchain GCC 3.2 GCC 3.4 GCC 4.1 GCC 4.4 GCC 4.8.2
Languages supported 10 15 19 22 22
NIAP/CC certified11 Yes (3+) Yes (4+) Yes (4+) Yes (4+) Under Evaluation (4+)
Common Criteria certified KVM11 -- -- Evaluated Evaluated Under Evaluation
IPv6 -- -- Ready Logo Phase 2 Ready Logo Phase 2 Under Evaluation
FIPS certified11 -- -- Yes (7 modules) Yes (8 modules) Under Evaluation (9 modules)
Common Operating Environment (COE) compliant Yes Yes N/A N/A N/A
LSB-compliant Yes - 1.3 Yes - 3 Yes - 3.1 Yes - 4.0 Under Evaluation (4.1)
GB18030 No Yes Yes Yes Yes
Client environment
Desktop GUI Gnome 2.2 Gnome 2.8 Gnome 2.16 Gnome 2.28 Gnome 3.8
Graphics XFree86 X.org X.org 7.1.1 X.org 7.4 X.org 7.7
OpenOffice V1.1 V1.1.2 V2.0.4 12 V3.2 12 LibreOffice V4.1.4 12
Gnome Evolution V1.4 V2.0 V2.8.0 V2.28 V3.8.5
Default browser Mozilla Firefox Firefox 1.5 12 Firefox 3.6 12 Firefox 24.5 12

Legend:

Values are depicted as tested/supported [theoretical] above.

Notes:

1. Supported limits reflect the current state of system testing by ClearOS and its partners for mainstream hardware. Systems exceeding these supported limits may be included in the Hardware Catalog after joint testing between ClearOS 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 ClearOS subscription terms. Supported limits are subject to change as ongoing testing completes.
2. ClearOS defines a logical CPU as any schedulable entity. So every core/thread in a multicore/thread processor is a logical CPU.
3. 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.
4. The x86 "Hugemem" kernel is not provided in ClearOS 5 or 6.
5. The architectural limits are based on the capabilities of the ClearOS kernel and the physical hardware. ClearOS 6 limit is based on 46-bit physical memory addressing. ClearOS 5 limit is based on 40-bit physical memory addressing. All system memory should be balanced across NUMA nodes in a NUMA-capable system.
6. ClearOS 6 does not include support for the Itanium 2 architecture. ClearOS 7 does not include support for the Itanium 2 and 32-bit x86 architectures.
7. 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.
8. Officially support 125 CPUs across the entire machine.
9. Requires Intel EPT and AMD RVI technology support.
10. UEFI and GPT support required for more that 2TB boot LUN support.
11. Get security certification details.
12. Firefox, Thunderbird, and OpenOffice applications will be updated during the life cycle.
13. Larger numbers are possible, depending on testing and support by the specific hardware vendor. For example, EMC supports up to 8,192 device paths on ClearOS 5. Consult your hardware vendor to determine their limit, and confirm with your ClearOS support representative. In no case will ClearOS support a limit that exceeds the limit supported by the hardware vendor.
14. It may be necessary to increase certain driver parameters to reach these limits. Consult with your ClearOS support representative.
15. ClearOS 6.7 is required for support of 12TB of RAM. ClearOS 6.6 can support up to 6TB of RAM. Previous versions of ClearOS 6, starting with ClearOS 6.3, support up to 3TB of RAM. Versions of ClearOS prior to ClearOS 6.3 support up to 1TB of RAM.
16. ClearOS 7.2 is required for support of 12TB of RAM. ClearOS 7.1 can support up to 6TB of RAM. Previous versions of ClearOS 7 (i.e. ClearOS 7.0) support up to 3TB of RAM.
17. ClearOS 7.1 or newer, or ClearOS 6.7 or newer is required for 288 CPU support. The previous maximum supported CPU count for earlier versions was 240 CPUs.
18. ClearOS 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.