Veritas Storage Foundation 5.0.1 Cluster File System Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

NOTE: The default activation mode for shared disk groups is off.
Applications such as high availability and off-host backup can use disk group activation to
explicitly control volume access from different nodes in the cluster.
The activation mode of a disk group controls volume I/O from different nodes in the cluster. It
is not possible to activate a disk group on a cluster node, if it is activated in a conflicting mode
on another node in the cluster.
Table 4-1 Activation Modes for Shared Disk Groups
DescriptionActivation Mode
The node has exclusive write access to the disk group. No other node can activate the
disk group for write access.
exclusive-write (ew)
The node has read access to the disk group and denies write access for all other nodes
in the cluster. The node has no write access to the disk group. Attempts to activate a
disk group for either of the write modes on other nodes will fail.
read-only (ro)
The node has read access to the disk group. The node has no write access to the disk
group, however other nodes can obtain write access.
shared-read (sr)
The node has write access to the disk group.
shared-write (sw)
The node has neither read or write access to the disk group. Query operations on the
disk group are permitted.
off
The following table summarizes allowed and conflicting activation modes or shared disk groups:
Table 4-2 Allowed and Conflicting Activation Modes
Attempt to activate disk group on another node as...Disk group activated
in cluster as...
shared-writeshared-readread-onlyexclusive- write
FailsSucceedsFailsFails
exclusive-write
FailsSucceedsSucceedsFails
read-only
SucceedsSucceedsSucceedsSucceeds
shared-read
SucceedsSucceedsFailsFails
shared-write
Shared disk groups can be automatically activated in any mode during disk group creation or
during manual or auto-import. To control auto-activation of shared disk groups, the defaults
file /etc/default/vxdg must be created.
The defaults file /etc/default/vxdg must contain the following lines:
enable_activation=true default_activation_mode=activation-mode
Where activation-mode is one of the following:
• exclusive-write
• read-only
• shared-read
• shared-write
• off
To view the activation mode setting for each of your shared disk groups, enter:
# cfsdgadm display
When a shared disk group is created or imported, it is activated in the specified mode. When a
node joins the cluster, all shared disk groups accessible from the node are activated in the specified
mode.
32 Cluster Volume Manager Administration