Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

As using the -f option to force the import of an incomplete disk group counts as
a successful import, an incomplete disk group may be imported subsequently
without this option being specified. This may not be what you expect.
You can also import the disk group as a shared disk group.
See “Importing disk groups as shared” on page 455.
These operations can also be performed using the vxdiskadm utility. To deport a
disk group using vxdiskadm, select Remove access to (deport) a disk group
from the main menu. To import a disk group, select 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 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.
VxVM chooses minor device numbers for objects created from this disk group
starting at the base minor number base_minor. Minor numbers can range from
this value up to 16,777,215. 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.
VxVM reserves the range of minor numbers from 0 to 999 for use with volumes
in the boot disk group. For example, the rootvol volume is always assigned minor
number 0.
If you do not specify the base of the minor number range for a disk group, VxVM
chooses one at random. The number chosen is at least 1000, is a multiple of 1000,
and yields a usable range of 1000 device numbers. The chosen number also does
not overlap within a range of 1000 of any currently imported disk groups, and it
does not overlap any currently allocated volume device numbers.
229Creating and administering disk groups
Moving disk groups between systems