Disabling Defrag for Red Hat and CentOS Systems

On all Red Hat and CentOS systems, you must disable the defrag utility to meet Vertica configuration requirements. The steps necessary to disable defrag on Red Hat 6/CentOS 6 systems differ from those used to disable defrag on Red Hat 7/CentOS 7 systems.

Disable Defrag on Red Hat 6/CentOS 6 Systems

  1. Determine if defrag is enabled by running the following command:
    cat /sys/kernel/mm/redhat_transparent_hugepage/defrag
    [always] madvise never

    The setting returned in brackets is your current setting. If you are not using madvise or never as your defrag setting, then you must disable defrag.

  2. Edit /etc/rc.local, and add the following script:
    if test -f /sys/kernel/mm/redhat_transparent_hugepage/enabled; then
        echo never > /sys/kernel/mm/redhat_transparent_hugepage/defrag
    fi
  3. You must reboot your system for the setting to take effect, or run the following echo line to proceed with the install without rebooting:

    # echo never > /sys/kernel/mm/redhat_transparent_hugepage/defrag

Disable Defrag on Red Hat 7/CentOS 7 Systems

  1. Determine if defrag is enabled by running the following command:
    cat /sys/kernel/mm/transparent_hugepage/defrag
    [always] madvise never

    The setting returned in brackets is your current setting. If you are not using madvise or never as your defrag setting, then you must disable defrag.

  2. Edit /etc/rc.local, and add the following script:
    if test -f /sys/kernel/mm/transparent_hugepage/enabled; then
        echo never > /sys/kernel/mm/transparent_hugepage/defrag
    fi
  3. You must reboot your system for the setting to take effect, or run the following echo line to proceed with the install without rebooting:

    # echo never > /sys/kernel/mm/transparent_hugepage/defrag
  4. If you are using Red Hat 7.0 or CentOS 7.0 or higher, run the following command as root or sudo:
    $ chmod +x /etc/rc.d/rc.local