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

If a minor conflict exists when a disk group is imported, VxVM automatically
assigns a new base minor to the disk group, and reminors the volumes in the disk
group, based on the new base minor. You do not need to run the vxdg reminor
command to resolve the minor conflicts.
To avoid any conflicts between shared and private disk groups, the minor numbers
are divided into shared and private pools. VxVM allocates minor numbers of
shared disk groups only from the shared pool, and VxVM allocates minor numbers
of private disk groups only from the private pool. If you import a private disk
group as a shared disk group or vice versa, the device minor numbers are
re-allocated from the correct pool. The disk group is dynamically reminored.
By default, private minor numbers range from 0-32999, and shared minor numbers
start from 33000. You can change the division, if required. For example, you can
set the range for shared minor numbers to start from a lower number. This range
provides more minor numbers for shared disk groups and fewer minor numbers
for private disk groups.
Normally, the minor numbers in private and shared pools are sufficient, so there
is no need to make changes to the division.
Note: To make the new division take effect, you must run vxdctl enable or restart
vxconfigd after the tunable is changed in the defaults file. The division on all the
cluster nodes must be exactly the same to prevent node failures for node join,
volume creation, or disk group import operations.
To change the division between shared and private minor numbers
1
Add the tunable sharedminorstart to the defaults file /etc/default/vxsf.
For example, to change the shared minor numbers so that the range starts
from 20000, set the following line in the /etc/default/vxsf file.
sharedminorstart=20000
You cannot set the shared minor numbers to start at less than 1000. If
sharedminorstart is set to values between 0 to 999, the division of private
minor numbers and shared disk group minor numbers is set to 1000. The
value of 0 disables dynamic renumbering.
2
Run the following command:
# vxdctl enable
In certain scenarios, you may need to disable the division between shared minor
numbers and private minor numbers. For example, you may need to prevent the
device minor numbers from being changed when you upgrade from a previous
225Creating and administering disk groups
Handling of minor number conflicts