Veritas™ Volume Manager Administrator's Guide

Handling of minor number conflicts

The volume device minor numbers in a disk group to be imported may conflict with existing volume devices. In previous releases of VxVM, the conflicts resulted in failures. Either the disk group import operation failed, or the slave node failed to join a shared disk group. When this situation happened, you had to run the vxdg reminor command manually to resolve the minor conflicts. Starting with this release, VxVM can automatically resolve minor number conflicts.

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.

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 release. In this case, disable the dynamic reminoring before you install the new VxVM package.