Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Chapter 3, Administering Dynamic Multipathing (DMP)
Disabling and Enabling Multipathing for Specific Devices
107
at least one primary path is enabled. When all the primary paths have become
disabled, all the paths are shown as SECONDARY. Any path attributes are only
changed when device discovery is performed.
◆ DMP does not perform failover when a path to a LUN fails. DMP still shows the state
of the path as active until HP-UX native multipathing fails an I/O or ioctl request
on that path.
◆ The output from the DMP vxdmpadm iostat command does not match the output
from the native HP-UX iostat command.
◆ Using the vxdmpadm disable and enable commands on a path or controller causes
DMP to use another path for I/O, but HP-UX native multipathing may still be
sending I/O to the disabled path or controller.
Disabling and Enabling Multipathing for Specific Devices
You can use vxdiskadm menu options 17 and 18 to disable or enable multipathing. These
menu options also allow you to exclude devices from or include devices in the view of
VxVM. For more information, see “Disabling Multipathing and Making Devices Invisible
to VxVM” on page 107 and “Enabling Multipathing and Making Devices Visible to
VxVM” on page 108.
Disabling Multipathing and Making Devices Invisible to VxVM
Note Some of the operations described in this section require a reboot of the system.
1. Select menu task 17 (Prevent multipathing/Suppress devices from
VxVM’s view) from the vxdiskadm main menu to prevent a device from being
multipathed by the VxVM DMP driver (vxdmp), or to exclude a device from the view
of VxVM. You are prompted to confirm whether you want to continue.
2. Select the operation you want to perform from the displayed list:
1 Suppress all paths through a controller from VxVM’s view
2 Suppress a path from VxVM’s view
3 Suppress disks from VxVM’s view by specifying a VID:PID
combination
4 Suppress all but one paths to a disk
5 Prevent multipathing of all disks on a controller by VxVM
6 Prevent multipathing of a disk by VxVM
7 Prevent multipathing of disks by specifying a VID:PID
combination
8 List currently suppressed/non-multipathed devices