UltraPath

If you use UltraPath, retain the default initiator settings. Do not select Uses third-party multipath software.

Figure 6-4 Initiator setting when UltraPath is used

To change the LUN mapping on the storage system, including but not limited to changing the host LUN ID, changing the port online, and removing and adding a LUN, follow the instructions in FAQs in the OceanStor UltraPath for AIX User Guide to correctly change the LUN mapping. Otherwise, services may be interrupted.

Install UltraPath by following instructions in the OceanStor UltraPath for AIX User Guide.

After you install UltraPath, set the trespass policy for LUNs as follows:

• This configuration must be performed on all hosts separately. Retain the default settings for other parameters.
• In SAN Boot mode, the virtual LUN running the host's operating system must be a common virtual LUN. You can change a common virtual LUN to a HyperMetro virtual LUN only after UltraPath is installed on the host and the host is restarted.
• When N_Port_ID virtualization (NPIV) coupled with Virtual I/O Server (VIOS) is used, the requirements of NPIV on hardware and software must be met.
• When NPIV coupled with VIOS is used, UltraPath must be installed on the client AIX partition.

• For UltraPath earlier than 21.2.0, it is recommended that you run the set luntrespass command to disable the trespass policy.

  UltraPath CLI #3 >set luntrespass=off 
  The current configuration will overwrite the configuration of all VLUNs in this array.  
  Are you sure you want to continue? [y,n]: y  
  Succeeded in executing the command.

  The command format is set luntrespass={ on | off } [ array_id=ID | vlun_id={ ID | ID1,ID2... | ID1-ID2 } ]. Table 6-4 describes the key parameters in the command.

  Table 6-4 Parameter description

  Parameter	Description	Default Value
  { on | off }	Trespass policy of LUNs on: Switchover of LUNs' working controller is enabled. off: Switchover of LUNs' working controller is disabled.	on
  array_id=ID	ID of the storage array You can run the show array command to query the ID of the storage array.	None
  vlun_id={ ID | ID1,ID2... | ID1-ID2 }	ID of the virtual LUN You can run the show vlun type=all command to query the IDs of all virtual LUNs.	None

• For UltraPath 21.2.0 and later, it is recommended that you retain the default settings (the trespass policy is disabled by default).