Chapter 2. Major Changes and Migration Considerations

This chapter discusses major changes and features that may affect migration from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7. Read each section carefully for a clear understanding of how your system will be impacted by upgrading to Red Hat Enterprise Linux 7.

2.1. System Limitations

Red Hat Enterprise Linux supported system limitations have changed between version 6 and version 7.
Red Hat Enterprise Linux 7 now requires at least 1 GB of disk space to install. However, Red Hat recommends a minimum of 5 GB of disk space for all supported architectures.
AMD64 and Intel® 64 systems now require at least 1 GB of memory to run. Red Hat recommends at least 1 GB memory per logical CPU. AMD64 and Intel® 64 systems are supported up to the following limits:
  • at most 3 TB memory (theoretical limit: 64 TB)
  • at most 160 logical CPUs (theoretical limit: 5120 logical CPUs)
64-bit Power systems now require at least 2 GB of memory to run. They are supported up to the following limits:
  • at most 2 TB memory (theoretical limit: 64 TB)
  • at most 128 logical CPUs (theoretical limit: 2048 logical CPUs)
IBM System z systems now require at least 1 GB of memory to run, and are theoretically capable of supporting up to the following limits:
  • at most 3 TB memory
  • at most 101 logical CPUs
The most up to date information about Red Hat Enterprise Linux 7 requirements and limitations is available online at https://access.redhat.com/site/articles/rhel-limits. To check whether your hardware or software is certified, see https://access.redhat.com/certifications.