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The host producing the target repeatedly causes paths monitored by the multi-path is different with the actual mapping

Publication Date:  2012-12-05 Views:  92 Downloads:  0
Issue Description
The disk array and the host take the DAS network, the networking diagram is as followed:


In the above DAS networking mode, the connection mode of the disk array FC host port is Loop, after connecting successfully, draw out/in the controller or the fiber cable, there have redundant and useless paths in a path observed by the “upTools –S” in the host, and the service haven’t been influenced. As the following picture displayed:



Alarm Information
None
Handling Process
Restart the host.
Root Cause
The target redundancy produced in the host causes the paths displaying in the “upTools –S” are not correct. Observe the connections through the FC drive layer in the disk array, we find they are correct and there haven’t redundancy.

See from the SCSI layer, the mapping information of the LUN reported from the disk array is also right.

Analyze the information in the host, we find the target of the host has problem obviously, the same WWPN has created three targets, and the WWPN of the disk array controller A port is “0x20090022a10591b1”, use the following command to check the “systool -v -c fc_remote_ports”, as the following displayed:
Class = "fc_remote_ports"

  Class Device = "0-0"
  Class Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.0/host10/rport-10:0-0/fc_remote_ports/rport-10:0-0"
    dev_loss_tmo        = "30"
    fast_io_fail_tmo    = "off"
    node_name           = "0x21000022a10591b1"
    port_id             = "0x0000b4"
    port_name           = "0x20190022a10591b1"========================================》B控的WWPN
    port_state          = "Online"
    roles               = "FCP Target"
    scsi_target_id      = "0"
    supported_classes   = "unspecified"
    uevent              =

    Device = "rport-10:0-0"
    Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.0/host10/rport-10:0-0"
      uevent              =


  Class Device = "0-0"
  Class Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-0/fc_remote_ports/rport-11:0-0"
    dev_loss_tmo        = "30"
    fast_io_fail_tmo    = "off"
    node_name           = "0x21000022a10591b1"
    port_id             = "0x0000dc"
    port_name           = "0x20090022a10591b1”========================================》A控的WWPN
    port_state          = "Online"
    roles               = "FCP Target"
    scsi_target_id      = "0"
    supported_classes   = "unspecified"
    uevent              =

    Device = "rport-11:0-0"
    Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-0"
      uevent              =


  Class Device = "0-1"
  Class Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-1/fc_remote_ports/rport-11:0-1"
    dev_loss_tmo        = "30"
    fast_io_fail_tmo    = "off"
    node_name           = "0x21000022a10591b1"
    port_id             = "0x0000dc"
    port_name           = "0x20090022a10591b1“========================================》A控的WWPN
    port_state          = "Online"
    roles               = "FCP Target"
    scsi_target_id      = "1"
    supported_classes   = "unspecified"
    uevent              =

    Device = "rport-11:0-1"
    Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-1"
      uevent              =


  Class Device = "0-2"
  Class Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-2/fc_remote_ports/rport-11:0-2"
    dev_loss_tmo        = "30"
    fast_io_fail_tmo    = "off"
    node_name           = "0x21000022a10591b1"
    port_id             = "0x0000dc"
    port_name           = "0x20090022a10591b1”========================================》A控的WWPN
    port_state          = "Online"
    roles               = "FCP Target"
    scsi_target_id      = "2"
    supported_classes   = "unspecified"
    uevent              =

    Device = "rport-11:0-2"
    Device path = "/sys/devices/pci0000:00/0000:00:07.0/0000:1f:00.1/host11/rport-11:0-2"
      uevent              =

The multi-path has obtained the LUN information through “host -> target-> lun”, the host11 has extra two “target”, which causes it is more than the redundancy twice LUN, the “target” in the host are determined by the port_id and port_name, and the two items of the three “target” in the host11 are the same, there should be only one “target”.



Suggestions
Once meet this problem, we suggest contacting the producer of the host or the HBA to acquire assist.

END