Replacing 7-Mode LUN WWIDs on Linux hosts after transition of LUNs

Contributors netapp-ivanad ntap-bmegan Download PDF of this page

After LUN transition, the 7-Mode LUN WWID changes. You must replace it with the corresponding ONTAP LUN WWID before you can begin servicing data.

If you are doing a copy-free transition (CFT), then 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 is complete.

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

    • For CBTs, 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 CFTs, 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 new ONTAP LUN device handle ID from 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 new ONTAP LUNs:

    rescan-scsi-bus.sh

  5. Identify the SCSI devices of the new ONTAP LUNs:

    sanlun lun show

  6. Get the WWIDs for the new ONTAP LUNs:

    /lib/udev/scsi_id -g -u -d /dev SCSI_dev

  7. If a DMMP alias is defined, then update the /etc/multipath.conf file to replace the 7-Mode LUN WWID with its corresponding ONTAP LUN WWID, so that the DMMP alias points to the clustered Data ONTAP LUN:

    cat /etc/multipath.conf

  8. Configure the DMMP devices:

    multipath

  9. Verify that the DMMP alias is correctly referencing the ONTAP LUN WWID:

    multipath -11

    In the following sample output, the DMMP alias dmmp_raw_lun is referencing 3600a098051764b2d4f3f453135452d31 as the ONTAP WWID:

    root@IBMx3550M3-229-169 ~]# multipath -ll dmmp_raw_lun
    dmmp_raw_lun (3600a098051764b2d4f3f453135452d31) dm-8 NETAPP, LUN C-Mode
    [size=1.0G] [features=3 queue_if_no_path pg_init_retries 50] [hwhandler=1 alua] [rw]
    \_round-robin 0 [prio=50][enabled]
     \_5:0:0:6 sdx 	65:112 [active][ready]
    	\_8:0:0:6 sdab 65:176 [active][ready]
    \_round-robin 0 [prio=10][enabled]
     \_6:0:0:6 sdy 	65:128 [active][ready]
    	\_7:0:0:6 sdaa 65:160 [active][ready]