Configuring DMP support for booting over a SAN

Article:HOWTO74814  |  Created: 2012-03-27  |  Updated: 2012-03-27  |  Article URL http://www.symantec.com/docs/HOWTO74814
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How To


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Subject


Configuring DMP support for booting over a SAN

See Configuring DMP for SAN booting

For DMP to work with an LVM root disk over a SAN, configure the system to use the boot device over all possible paths.

To configure DMP support for booting over a SAN

  1. Verify that each path to the root device has the same physical volume identifier (PVID) and the same volume group. Use the lspv command for the root volume group to verify that the PVID and volume group entries are set correctly. The PVID and volume group entries in the second and third columns of the output should be identical for all the paths.

    In this example, the LVM root disk is multi-pathed with four paths. The output from the lspv command for the root volume group (rootvg) is as follows:

    # lspv | grep rootvg
    hdisk374 00cbf5ce56def54d rootvg active
    hdisk375 00cbf5ce56def54d rootvg
    hdisk376 00cbf5ce56def54d rootvg
    hdisk377 00cbf5ce56def54d rootvg
  2. If the PVID and volume group entries are not set correctly on any of the paths, use the chdev command to set the correct value.

    For example, the following output shows that the hdisk377 path is not set correctly:

    # lspv
    hdisk374 00cbf5ce56def54d rootvg active
    hdisk375 00cbf5ce56def54d rootvg
    hdisk376 00cbf5ce56def54d rootvg
    hdisk377 none             None

    To set the PVID for the path, use the following command:

    # chdev -l hdisk377 -a pv=yes
    hdisk377 changed

    The output of the lspv command now shows the correct values:

    # lspv | grep rootvg
    hdisk374 00cbf5ce56def54d rootvg active
    hdisk375 00cbf5ce56def54d rootvg
    hdisk376 00cbf5ce56def54d rootvg
    hdisk377 00cbf5ce56def54d rootvg
  3. Set the boot list to include all the paths of current boot disk.

    # bootlist -m normal hdisk374 hdisk375 hdisk376 hdisk377 blv=hd5

    Verify that the boot list includes all paths and that each path shows the default boot volume hd5:

    # bootlist -m normal -o
    hdisk374 blv=hd5
    hdisk375 blv=hd5
    hdisk376 blv=hd5
    hdisk377 blv=hd5
  4. If the blv option is not set for a path to the disk, use the bootlist command to set it. For example:

    # bootlist -m normal hdisk374 hdisk375 hdisk376 hdisk377 blv=hd5
  5. Run one of the following commands to configure DMP on the root disk:

    • The recommended method is to turn on DMP support for LVM volumes, including the root volume.

      # vxdmpadm settune dmp_native_support=on
    • The following command enables DMP support for LVM volumes only for the root disk. This method will be deprecated in a future release.

      # vxdmpadm native enable vgname=rootvg
  6. Reboot the system. DMP takes control of the SAN boot device to perform load balancing and failover.

  7. Verify whether DMP controls the root disk.

    # vxdmpadm native list vgname=rootvg
    PATH           DMPNODENAME
    ===========================
    hdisk374       ams_wms0_491
    hdisk375       ams_wms0_491
    hdisk376       ams_wms0_491
    hdisk377       ams_wms0_491

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