Preparing for transition of FC or FCoE SAN boot LUNs on RHEL hosts

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Before you transition an FC or FCoE SAN boot LUN, you must perform specific steps on your Red Hat Enterprise Linux (RHEL) host.

You must have the following information from the Inventory Assessment Workbook:

  • 7-Mode LUN name on which RHEL 5 or RHEL 6 is installed

  • SCSI device name for the transition LUN

  • DMMP device name for the transition LUN

  • Mount directory

  • File system configured on the DMMP device

  • UUID number of the /boot partition

  • Name of the initrid image

This procedure applies to copy-based transitions and copy-free transitions.

  1. Verify that the DMMP device exists in the /dev/mapper directory:

    ls /dev/mapper/ DMMP_device_name

    If you cannot locate the DMMP device, then it might be using an alias or user-friendly name.

  2. Identify the DMMP devices and Logical Volume Manager (LVM) names on which the RHEL 5 or RHEL 6 operating system /boot and root (/) directories are installed:

    df - h

    By default, RHEL 5 and RHEL 6 are installed on the root (/) partition on the logical volume. If the root partition is installed on the logical volume, then no pretransition changes to the configuration are required.

  3. If the /boot partition is installed on the DMMP device, confirm how the /boot partition is referenced to mount in /etc/fstab at boot time.

  4. If the /boot partition is referenced in /etc/fstab by its DMMP device name, replace the DMMP device name with the file system UUID name.

  5. Make a backup of the /etc/fstab file:

    cp /etc/fstab /etc/fstab_pre_transition_file_name

  6. Edit the /etc/fstab file to replace the DMMP device name with its respective file system UUID number.

  7. Make a backup of the initrd image file:

    cp /boot/initrd_image_file_nameinitrd_image_file_name.bak

  8. For RHEL 5 only:

    1. In the /etc/mutipath.conf file, identify the SWAP partition device.

      In the following example, /dev/VolGroup00/LogVol01 is the SWAP partition device:

      /dev/VolGroup00/LogVol01 swap swap defaults 0 0

    2. Create a label for mounting the swap partition:
      swapoff swap-partition_device

      mkswap -L label-for-swapswap-partition-device

      swapon swap-partition_device

    3. Replace the SWAP partition device name in the /etc/fstab file with THE SWAP label.

      The updated line in the /etc/fstab file should be as follows:

      LABEL=SwapPartition  swap  swap   defaults    0 0
  9. Re-create the initrd image.

    • For RHEL5:
      mkinitrd -f/boot/ initrd-"'uname-r'".img 'uname-r' --with multipath

    • For RHEL 6:
      dracut --force --add multipath --verbose

  10. Restart the host to boot from the new initrd image.

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