Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

392 Administering cluster functionality
Overview of cluster volume management
The following table summarizes the allowed and conflicting activation modes for shared
disk groups:
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
The activation-mode is one of exclusivewrite, readonly, sharedread,
sharedwrite, or off.
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.
readonly (ro) 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 fail.
sharedread (sr) 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.
sharedwrite (sw) The node has write access to the disk group.
off The node has neither read nor write access to the disk group. Query
operations on the disk group are permitted.
Table 13-2 Allowed and conflicting activation modes
Disk group activated
in cluster as...
Attempt to activate disk group on another node as...
exclusive-
write
readonly sharedread sharedwrite
exclusivewrite
Fails Fails Succeeds Fails
readonly
Fails Succeeds Succeeds Fails
sharedread
Succeeds Succeeds Succeeds Succeeds
sharedwrite
Fails Fails Succeeds Succeeds
Table 13-1 Activation modes for shared disk groups
Activation mode Description