16.17.5. Recommended Partitioning Scheme

Unless you have a reason for doing otherwise, we recommend that you create the following partitions:
  • A swap partition (at least 256 MB) — Swap partitions support virtual memory: data is written to a swap partition when there is not enough RAM to store the data your system is processing.
    In years past, the recommended amount of swap space increased linearly with the amount of RAM in the system. Modern systems often include hundreds of gigabytes of RAM, however. As a consequence, recommended swap space is considered a function of system memory workload, not system memory.
    The following table provides the recommended size of a swap partition depending on the amount of RAM in your system and whether you want sufficient memory for your system to hibernate. The recommended swap partition size is established automatically during installation. To allow for hibernation, however, you will need to edit the swap space in the custom partitioning stage.

    Table 16.2. Recommended System Swap Space

    Amount of RAM in the system Recommended swap space Recommended swap space if allowing for hibernation
    ⩽ 2GB 2 times the amount of RAM 3 times the amount of RAM
    > 2GB – 8GB Equal to the amount of RAM 2 times the amount of RAM
    > 8GB – 64GB 0.5 times the amount of RAM 1.5 times the amount of RAM
    > 64GB 4GB of swap space No extra space needed

    At the border between each range listed above (for example, a system with 2GB, 8GB, or 64GB of system RAM), discretion can be exercised with regard to chosen swap space and hibernation support. If your system resources allow for it, increasing the swap space may lead to better performance.
    Note that distributing swap space over multiple storage devices — particularly on systems with fast drives, controllers and interfaces — also improves swap space performance.

    Note

    Swap space size recommendations issued for Red Hat Enterprise Linux 6.0, 6.1, and 6.2 differed from the current recommendations, which were first issued with the release of Red Hat Enterprise Linux 6.3 in June 2012 and did not account for hibernation space. Automatic installations of these earlier versions of Red Hat Enterprise Linux 6 still generate a swap space in line with these superseded recommendations. However, manually selecting a swap space size in line with the newer recommendations issued for Red Hat Enterprise Linux 6.3 is advisable for optimal performance.
  • A PReP boot partition on the first partition of the hard drive — the PReP boot partition contains the Yaboot boot loader (which allows other Power Systems servers to boot Red Hat Enterprise Linux). Unless you plan to boot from a network source, you must have a PReP boot partition to boot Red Hat Enterprise Linux.
    For IBM System p users: The PReP boot partition should be between 4-8 MB, not to exceed 10 MB.
  • A /boot/ partition (250 MB) — the partition mounted on /boot/ contains the operating system kernel (which allows your system to boot Red Hat Enterprise Linux), along with files used during the bootstrap process. Due to the limitations of most PC firmware, creating a small partition to hold these is a good idea. For most users, a 250 MB boot partition is sufficient.

    Warning

    If you have a RAID card, be aware that Red Hat Enterprise Linux 6.5 does not support setting up hardware RAID on an IPR card. You can boot the standalone diagnostics CD prior to installation to create a RAID array and then install to that RAID array.
  • A root partition (3.0 GB - 5.0 GB) — this is where "/" (the root directory) is located. In this setup, all files (except those stored in /boot) are on the root partition.
    A 3.0 GB partition allows you to install a minimal installation, while a 5.0 GB root partition lets you perform a full installation, choosing all package groups.

    Root and /root

    The / (or root) partition is the top of the directory structure. The /root directory (sometimes pronounced "slash-root") is the home directory of the user account for system administration.

Warning

The PackageKit update software downloads updated packages to /var/cache/yum/ by default. If you partition the system manually, and create a separate /var/ partition, be sure to create the partition large enough (3.0 GB or more) to download package updates.