How do I rebuild the initramfs with multipath in Red Hat Enterprise Linux

Environment

• Red Hat Enterprise Linux 6
• Red Hat Enterprise Linux 7
• Red Hat Enterprise Linux 8
• Red Hat Enterprise Linux 9
• device-mapper-multipath
• initramfs

Issue

• How do I rebuild the initramfs with multipath.
• What parameters I need to modify to include multipath modules in initramfs file?
• multipath modules and configuration files are missing in initramfs image while installing new kernel in RHEL.

Resolution

1. It is recommended you make a backup copy of the initramfs in case the new version has an unexpected problem:

    # cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.$(date +%m-%d-%H%M%S).bak
   

2. Now rebuild the initramfs image with multipath, execute the dracut command with the following options:

    # dracut -v -f -a multipath --include /etc/multipath /etc/multipath
   

3. Alternatively, edit /etc/dracut.conf and modify the add_dracutmodules line:

   Find:

    # Dracut modules to add to the default
    #add_dracutmodules+=""
   

   Change to:

    # Dracut modules to add to the default
    add_dracutmodules+=" multipath "
   

   Rebuild initramfs:

    # dracut -v -f /boot/initramfs-$(uname -r).img $(uname -r)
   

4. For RHEL7 you may want to follow Red Hat' s Documentation. For later kernel versions refernce the corresponding DM Multipath Guides.

5. Reboot the system with newly created initramfs image.

Root Cause

For RHEL6 Following Bug report and Errata are related:

• This has been identified in the following BZ This content is not included.642083
• Which is addressed in the following errata: RHBA-2011-0523:

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