Notes on changing the HDLM device configuration

Note the following when changing the HDLM device configuration:

• When an HDLM device is excluded from HDLM management, the AutoPATH_IDs assigned to the paths for that device will be released. Because of this, after paths for an HDLM device are released, the AutoPATH_IDs of the paths may be displayed in a non-consecutive sequence.

• When an HDLM device is included in HDLM management, HDLM assigns an AutoPATH_ID in sequential order (from the lowest available number) to the path of that HDLM device.

• When an HDLM device that is not managed by HDLM is included in HDLM management, HDLM places online all the normal paths to that HDLM device regardless of the previous status (such as Online(E) or Offline(C)) of the path.

• Do not execute the HDLM-configuration definition utility (dlmcfgmgr) with the -o, -i, or -u parameter while the LU is in use (for example, when performing I/O or a mount).

• If a disk partition is created or changed while some of the paths for an LU are disconnected, the disk partition may not be recognized even after the disconnected paths have been recovered. After connecting the disconnected paths, execute the dlmcfgmgr utility or restart the host.

• When the dlmcfgmgr utility is executed to change the HDLM device configuration, memory might become insufficient due to the HAL daemon^#. In this case, the host will not respond.

  To avoid this, stop the HAL daemon when executing the dlmcfgmgr utility. For details on how to stop the HAL daemon, see NOTES_ON_INSTALLING_HDLM=GUID-82C4C427-8D81-44B3-B1CC-DB4EFDFCA042=6=EN=.html.

  This does not apply to Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Oracle Linux 7, Oracle Unbreakable Enterprise Kernel 7, Oracle Linux 8, Oracle Unbreakable Enterprise Kernel 8, or Oracle Linux 9.

  #

  The HAL daemon detects hardware configuration changes, for example, when a USB device or CD-ROM is inserted.

• If you execute the dlmcfgmgr utility with the -v parameter specified, a hyphen (-) might be displayed in the Device column as shown below:

  # dlmcfgmgr -v
  HDevName     Management  Device  Host Channel Target Lun
  /dev/sddlmaa configured /dev/sdd   3        0      0   0
                          /dev/sdk   3        0      1   0
                          /dev/sdr   4        0      0   0
                             -       4        0      1   0
  KAPL10302-I /sbin/dlmcfgmgr completed normally.

  This state might be caused by the following operations:

  • Restarting the host when the paths are disconnected

  • Restarting the host after deleting an LU

  • Restarting the host after changing the fiber cable connection

  • Restarting the host after changing the zone settings for the Fibre Channel switch

  If you want to delete the path whose status is indicated by a hyphen (-), execute the dlmcfgmgr utility with the -u parameter specified.

  For details on this utility, see DLMCFGMGR_UTILITY_FOR_MANAGING_THE_HDLM_CONFIGURATION=GUID-206DE304-3FED-4BCC-AD77-A75B4DC0E01D=2=EN=.html.

• If you deallocate an existing LU and then allocate a new LU to the path that was used by the deallocated LU, the HDLM device that is allocated to the LU is also changed. In this case, the HDLM device that had been allocated to the deallocated LU is deleted and a new HDLM device is allocated to the new LU.

  Also, if you replace an existing storage system by a new storage system, a new HDLM device is allocated to each LU in the storage system even if the LU configuration of the new storage system is the same as the LU configuration of the replaced storage system.