Remounting LUNs with mount points using DMMP alias names on Linux hosts after transition

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After transition from ONTAP operating in 7-Mode to clustered Data ONTAP, you must remount your LUNs with mount points. The7-Mode volumes are offline and the 7-Mode LUNs are not accessible to your hosts.

If you are doing a copy-free transition (CFT), procedures for vol rehost must be complete.

  • For copy-based transitions (CBTs), perform these steps after completing the Storage Cutover operation in the 7MTT.

  • For CFTs, perform these steps after the Import Data & Configuration operation in the 7MTT.

    1. Generate the 7-Mode to ONTAP LUN mapping file:

      • For copy-based transitions, run the following command from the Linux host where the 7MTT is installed:
        transition cbt export lunmap -p project-name -o file_path

        For example:

        transition cbt export lunmap -p SanWorkLoad -o c:/Libraires/Documents/7-to-C-LUN-MAPPING.csv

      • For copy-free transitions, run the following command from the system where the 7MTT is installed:
        *transition cft export lunmap -p project-name -s svm-name -o output-file

        For example:

        transition cft export lunmap -p SanWorkLoad -s svml -0 c:/Libraries/Documents/7-to-C-LUN-MAPPING-svml.csv

        You must run this command for each of your storage virtual machines (SVMs).
    2. Make a note of the ONTAP device handle ID in the LUN mapping file.

    3. Remove the SCSI devices created for 7-Mode LUNs:

      • To remove all of the SCSI devices:
        rescan-scsi-bus.sh -r

      • To remove each SCSI device individually:
        *echo 1> /sys/block/SCSI_ID/delete_

        This command must be executed on all 7-Mode LUN SCSI devices. See the SCSI Device ID column on the SAN Host LUNs tab of the Inventory Assessment Workbook to identify the SCSI device IDs for the LUNs.

    4. Discover the new ONTAP LUNs:

      rescan-scsi-bus.sh

    5. Verify that the ONTAP LUNs are discovered:

      sanlun lun show

      The ONTAP LUN’s SCSI devices should be listed in the device filename column.

      An example of a SCSI device name is /dev/sdp.

    6. In the /etc/multipath.conf file, replace the 7-Mode device handle ID with the clustered Data ONTAP LUN’s device handle ID so that the alias name points to the clustered Data ONTAP LUN ID.

      You should update the multipaths section as displayed below. The following example shows the /etc/multipath.conf file, before replacing the 7-Mode LUN ID. In this example, the LUN ID 360a9800037534562572b453855496b43 is pointing to the dmmp_fs_lun alias name.

      multipaths {
              multipath {
                   wwid	360a9800037534562572b453855496b43
                   alias		dmmp_fs_lun
          }
      }

      After replacing the 7-Mode LUN ID with the ONTAP LUN ID 360a9800037534562572b453855496b43, the example files looks as follows:

      multipaths {
              multipath {
                   wwid	3600a098051764937303f4479515a7452
                   alias		dmmp_fs_lun
          }
      }
    7. Configure DMMP devices for ONTAP LUNs:

      multipath

    8. Verify that the DMMP alias points to the ONTAP LUN device handle ID:

      multipath -ll device_handle_ID

    9. Mount the ONTAP LUN to its mount point directory:

      mount /dev/mapper/alias_namemount_dir_name

      If the mount points are defined in the /etc/fstab file, use the mount -a command to mount the LUN.

    10. Verify that the DMMP device is mounted:

      mount