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

See “Setting the disk detach policy on a shared disk group” on page 482.
Table 13-3 summarizes the effect on a cluster of I/O failure to the disks in a
mirrored volume.
Table 13-3
Cluster behavior under I/O failure to a mirrored volume for different
disk detach policies
Global (diskdetpolicy=global)Local (diskdetpolicy=local)Type of I/O
failure
The plex is detached, and I/O
from/to the volume continues. An
I/O error is generated if no plexes
remain.
Reads fail only if no plexes remain
available to the affected node.
Writes to the volume fail.
Failure of path to
one disk in a
volume for a single
node
The plex is detached, and I/O
from/to the volume continues. An
I/O error is generated if no plexes
remain.
I/O fails for the affected node.Failure of paths to
all disks in a
volume for a single
node
The plex is detached, and I/O
from/to the volume continues. An
I/O error is generated if no plexes
remain.
The plex is detached, and I/O
from/to the volume continues. An
I/O error is generated if no plexes
remain.
Failure of one or
more disks in a
volume for all
nodes.
Disk group failure policy
The local detach policy by itself is insufficient to determine the desired behavior
if the master node loses access to all disks that contain copies of the configuration
database and logs. In this case, the disk group is disabled. As a result, any action
that would result in an update to log/config copy will also fail from the other
nodes in the cluster. In release 4.1, the disk group failure policy is introduced to
determine the behavior of the master node in such cases.
Table 13-4 shows how the behavior of the master node changes according to the
setting of the failure policy.
461Administering cluster functionality
Overview of cluster volume management