Managing Serviceguard Eighteenth Edition, September 2010

To initialize a disk for CVM, log on to the master node, then use the vxdiskadm
program to initialize multiple disks, or use the vxdisksetup command to initialize
one disk at a time, as in the following example:
/usr/lib/vxvm/bin/vxdisksetup -i c4t3d4
Creating Disk Groups
Use the following steps to create disk groups.
1. Use the vxdg command to create disk groups. Use the -s option to specify shared
mode, as in the following example:
vxdg -s init logdata c0t3d2
2. Verify the configuration with the following command:
vxdg list
NAME STATE ID
logdata enabled,shared 972078742.1084.node2
3. Activate the disk group, as follows, before creating volumes:
vxdg -g logdata set activation=sw
Mirror Detachment Policies with CVM
The default CVM disk mirror detachment policy is global, which means that as soon
as one node cannot see a specific mirror copy (plex), all nodes cannot see it as well.
The alternate policy is local, which means that if one node cannot see a specific mirror
copy, then CVM will deactivate access to the volume for that node only.
The global policy is recommended, because it ensures all nodes are accessing the same
current data. If you use local, it can cause problems if one node cannot update one of
the mirror copies and the data on that copy goes stale. If any of the other nodes read
from that mirror copy, they will read stale data. This can be avoided with the global
option, because all nodes will only use the current mirror copy, so they will all read
consistent data.
This policy can be reset on a disk group basis by using the vxedit command, as follows:
vxedit set diskdetpolicy=[global|local] <DiskGroupName>
NOTE: The specific commands for creating mirrored and multipath storage using
CVM are described in the HP-UX documentation for the Veritas Volume Manager,
posted at www.hp.com/go/hpux-core-docs.
Creating Volumes
Use the vxassist command to create volumes, as in the following example:
vxassist -g logdata make log_files 1024m
Configuring the Cluster 271