HP OpenVMS Systems Documentation

HP OpenVMS DCL Dictionary

Access to a MSCP/TMSCP class device may be available to an OpenVMS node from more than one host or storage controller. Use the SET PREFERRED_PATH command to specify a particular host or preferred path to access a specific MSCP class disk or TMSCP class tape device.

If a preferred path is specified, the normal OpenVMS path selection process is modified to select the user-specified path over other available paths, assuming the user-specified path is available.

This command is only meaningful for MSCP/TMSCP class devices that have more than one path available.

Format

SET PREFERRED_PATH device-name:

Parameter

device-name:

Specifies the name of a MSCP class disk or TMSCP class tape device.

Qualifiers

/HOST=host_name

Tells the MSCP/TMSCP class driver that you want this host to be the preferred access path to the specified device. The class driver remembers this host name until it is changed by taking one of the following actions:

• Issuing another SET PREFERRED_PATH command specifying a different host
• Using the /NOHOST qualifier
• Rebooting the system

Note that simply specifying a preferred path does not mean that it is immediately selected if the disk or tape device is currently using another path. Use the /FORCE qualifier along with the /HOST qualifier to force the preferred path to be used immediately.

The host_name is the name of the host that will be the preferred path to the disk or tape device.

/FORCE

Tells the class driver to initiate the path selection process immediately. If this qualifier is omitted when a new host name is specified, a switch from the current path to the new preferred path will not occur until some other event initiates the path selection process.

/NOHOST

Clears any previously defined preferred path assignment. Restores usual OpenVMS path selection behavior.

Examples

$ SET PREFERRED_PATH $10$DUA10: /HOST=HSC014
      

Prior to issuing this command, the $10$DUA10: disk device has host HSC015 as its primary path and host HSC014 as its secondary path. Issuing this command selects host HSC014 as the preferred path.

Note that the preferred path has been recorded by the class driver; however, the disk will remain on the current path (HSC015) until the next time the path selection process is initiated.

$ SET PREFERRED_PATH $10$DUA10: /HOST=HSC014 /FORCE
      

To make the path change occur immediately, include the /FORCE qualifier on the command line with the preferred path specification.

$ SET PREFERRED_PATH $10$DUA10: /FORCE
      

Issue this command to initiate path selection processing if the specified device has a primary path that differs from the preferred path.

If the preferred path is available, the device moves to that path.

$ SET PREFERRED_PATH $10$DUA10: /NOHOST
      

Remove the specified preferred path by using the /NOHOST qualifier if the device should no longer have a preferred path.