VERITAS Volume Manager 4.1 Administrator's Guide

Chapter 4 170
# vxdg -f import diskgroup
CAUTION Be careful when using the -f option. It can cause the same disk group to
be imported twice from different sets of disks, causing the disk group to
become inconsistent.
These operations can also be performed using the vxdiskadm utility. To
deport a disk group using vxdiskadm, select menu item 8 (Enable access
to (import) a disk group). The vxdiskadm import operation checks for
host import locks and prompts to see if you want to clear any that are
found. It also starts volumes in the disk group.
Reserving Minor Numbers for Disk Groups
A device minor number uniquely identifies some characteristic of a
device to the device driver that controls that device. It is often used to
identify some characteristic mode of an individual device, or to identify
separate devices that are all under the control of a single controller.
VxVM assigns unique device minor numbers to each object (volume, plex,
subdisk, disk, or disk group) that it controls.
When you move a disk group between systems, it is possible for the
minor numbers that it used on its previous system to coincide (or collide)
with those of objects known to VxVM on the new system. To get around
this potential problem, you can allocate separate ranges of minor
numbers for each disk group. VxVM uses the specified range of minor
numbers when it creates volume objects from the disks in the disk group.
This guarantees that each volume has the same minor number across
reboots or reconfigurations. Disk groups may then be moved between
machines without causing device number collisions.
To set a base volume device minor number for a disk group, use the
following command:
# vxdg init diskgroup minor=base_minor devicename
VxVM chooses minor device numbers for objects created from this disk
group starting at the number base_minor. Minor numbers can range
from 0 up to . Try to leave a reasonable number of unallocated minor
numbers near the top of this range to allow for temporary device number
remapping in the event that a device minor number collision may still
occur.