Configuration Information Cannot Be Found After LUN Mapping Is Canceled. Why?

Symptom

Partitions have been created for a LUN. The user cancels the LUN mapping and then uses the mpathadm command to query STMS multipathing information. An error message is returned, stating that the configuration information cannot be found and the operation cannot be performed.

bash-3.2# mpathadm list LU

        /dev/rdsk/c0t5000C500552839D3d0s2

                Total Path Count: 1

                Operational Path Count: 1

        /dev/rdsk/c0t5000C500552087F3d0s2

                Total Path Count: 1

                Operational Path Count: 1

        /dev/rdsk/c0t60022A1100041661001DBD4300000000d0s2

                Total Path Count: 2

                Operational Path Count: 2

        /dev/rdsk/c0t60022A1100041661001DF8EA00000001d0s2

                Total Path Count: 2

                Operational Path Count: 2

mpathadm:  Error: Unable to get configuration information.

mpathadm: Unable to complete operation

Root Cause

The mpathadm command queries information about all LUNs. If the host has residual information about the removed LUN, an error is returned when the command is executed.

Solution

Clear the residual LUN information as follows:

1. Run the cfgadm -al command to check the Ap_Ids of the FC mount points.

   In this example, c5 and c6 whose Type is fc-fabric are the FC mount points for the two HBA ports.

   bash-3.2# cfgadm -al 

   Ap_Id                          Type         Receptacle Occupant     Condition 

   c2                             scsi-sas     connected    configured unknown 

   c2::w5000c500552839d1,0        disk-path    connected    configured unknown 

   c3                           scsi-sas     connected    configured unknown 

   c3::w5000c500552087f1,0        disk-path    connected    configured unknown 

   c4                             scsi-sas     connected    unconfigured unknown 

   c5                             fc-fabric    connected    configured unknown 

   c5::201b0022a1041661           disk         connected    configured unknown 

   c6                             fc-fabric    connected    configured unknown 

   c6::200a0022a1041661           disk         connected    configured unknown

2. Manually unconfigure and configure the two mount points to update the LUN information.

   Although STMS works in round-robin mode, only one port (c6) has I/Os because ALUA is enabled on the array. When you unconfigure c6, an operation failure is returned. This return is normal and indicates that the operation does not affect the I/Os. This can be verified by the I/O monitoring statistics.

   bash-3.2# cfgadm -c unconfigure c5 

   bash-3.2# cfgadm -c unconfigure c6 

   cfgadm: Library error: remove operation failed: /devices/pci@77,0/pci8086,3c06@2,2/pci10df,f134@0,1/fp@0,0/disk@w200a0022a1041661,0: I/O error 

   remove operation failed: /devices/pci@77,0/pci8086,3c06@2,2/pci10df,f134@0,1/fp@0,0/disk@w200a0022a1041661,0: I/O error 

   failed to unconfigure ANY device on FCA port 

   bash-3.2# cfgadm -c configure c6 

   bash-3.2# cfgadm -c configure c5

3. Run the format command to check the LUN status. The residual information should be cleared.

   bash-3.2# format 

   Searching for disks...done 

   AVAILABLE DISK SELECTIONS: 

          0. c0t5000C500552087F3d0 <DEFAULT cyl 36469 alt 2 hd 255 sec 63> 

             /scsi_vhci/disk@g5000c500552087f3 

          1. c0t5000C500552839D3d0 <DEFAULT cyl 36469 alt 2 hd 255 sec 63> 

             /scsi_vhci/disk@g5000c500552839d3 

          2. c0t60022A1100041661001DBD4300000000d0 <DEFAULT cyl 2557 alt 2 hd 128 sec 32> 

             /scsi_vhci/disk@g60022a1100041661001dbd4300000000 

   Specify disk (enter its number):

4. Run the mpathadm command again. It is executed successfully.