Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

177Creating and administering disk groups
Moving disk groups between systems
Caution: Be careful when using the vxdisk clearimport or vxdg -C import command
on systems that have dual-ported disks. Clearing the locks allows those disks to be
accessed at the same time from multiple hosts and can result in corrupted data.
A disk group can be imported successfully if all the disks are accessible that were visible
when the disk group was last imported successfully. However, sometimes you may need
to specify the
-f option to forcibly import a disk group if some disks are not available. If
the import operation fails, an error message is displayed.
The following error message indicates a fatal error that requires hardware repair or the
creation of a new disk group, and of the disk group configuration and data:
VxVM vxdg ERROR V-5-1-587 Disk group groupname: import failed:
Disk group has no valid configuration copies
The following error message indicates a recoverable error.
VxVM vxdg ERROR V-5-1-587 Disk group groupname: import failed:
Disk for disk group not found
If some of the disks in the disk group have failed, you can force the disk group to be
imported by specifying the
-f option to the vxdg import command:
# 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. This can cause the disk group configuration to
become inconsistent.
See “Handling conflicting configuration copies” on page 180.
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.
These operations can also be performed using the vxdiskadm utility. To deport a disk
group using vxdiskadm, select menu item 8 (Remove access to (deport) a
disk group). To import a disk group, select item 7 (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.