1. 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.
2. Red Hat 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 Red Hat Enterprise Linux 5 or 6.
5. 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.
6. Red Hat Enterprise Linux 6 does not include support for the Itanium 2 architecture. Red Hat Enterprise Linux 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 (https://access.redhat.com/kb/docs/DOC-16981).
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 Red Hat Enterprise Linux 5. 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.
14. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
15. 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.
16. 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.
17. Red Hat Enterprise Linux 7.1 or newer, or Red Hat Enterprise Linux 6.7 or newer is required for 288 CPU support. The previous maximum supported CPU count for earlier versions was 240 CPUs.
18. 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.