Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Table 13-4
Behavior of master node for different failure policies
Disable
(dgfailpolicy=dgdisable)
Leave (dgfailpolicy=leave)Type of I/O
failure
The master node disables the disk
group.
The master node panics with the
message “klog update failed” for
a failed kernel-initiated
transaction, or “cvm config update
failed” for a failed user-initiated
transaction.
Master node loses
access to all copies
of the logs.
The behavior of the master node under the disk group failure policy is independent
of the setting of the disk detach policy. If the disk group failure policy is set to
leave, all nodes panic in the unlikely case that none of them can access the log
copies.
The vxdg command can be used to set the failure policy on a shared disk group.
See “Setting the disk group failure policy on a shared disk group” on page 482.
Guidelines for failure policies
If you have a critical disk group that you do not want to become disabled in the
case that the master node loses access to the copies of the logs, set the disk group
failure policy to leave. This prevents I/O failure on the master node disabling the
disk group. However, critical applications running on the master node fail if they
lose access to the other shared disk groups. In such a case, it may be preferable
to set the policy to dgdisable, and to allow the disk group to be disabled.
The default settings for the detach and failure policies are global and dgdisable
respectively. You can use the vxdg command to change both the detach and failure
policies on a shared disk group, as shown in this example:
# vxdg -g diskgroup set diskdetpolicy=local dgfailpolicy=leave
Effect of disk connectivity on cluster reconfiguration
The detach policy, previous I/O errors, or access to disks are not considered when
a new master node is chosen. When the master node leaves a cluster, the node
that takes over as master of the cluster may already have seen I/O failures for
one or more disks. Under the local detach policy, if a node was affected before
reconfiguration, and this node then becomes the master, the failure is treated
differently from the global detach policy case.
See “Connectivity policy of shared disk groups” on page 458.
Administering cluster functionality
Overview of cluster volume management
462