VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 10, Administering Cluster Functionality
Administering VxVM in Cluster Environments
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Creating a Shared Disk Group
Note Shared disk groups can only be created on the master node.
If the cluster software has been run to set up the cluster, a shared disk group can be
created using the following command:
# vxdg -s init diskgroup [diskname=]devicename
where diskgroup is the disk group name, diskname is the administrative name chosen for
a VM disk, and devicename is the device name (or disk access name).
Caution The operating system cannot tell if a disk is shared. To protect data integrity
when dealing with disks that can be accessed by multiple systems, use the
correct designation when adding a disk to a disk group. VxVM allows you to
add a diskthat isnot physically shared to ashareddisk group if thenode where
the disk is accessible is the only node in the cluster. However, this means that
other nodes cannotjoin thecluster. Furthermore,if youattempt to add the same
disk to different disk groups on two nodes at the same time, the results are
undefined. Perform all configuration on one node only, and preferably on the
master node.
Forcibly Adding a Disk to a Disk Group
Note Disks can only be forcibly added to a shared disk group on the master node.
If VxVM does not add a disk to an existing disk group because that disk is not attached to
the same nodes as the other disks in the disk group, you can forcibly add the disk using
the following command:
# vxdg -f adddisk -g diskgroup [diskname=]devicename
Caution Only use the forceoption(-f) ifyou arefully aware of the consequences suchas
possible data corruption.