Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Table 13-1
Activation modes for shared disk groups (continued)
DescriptionActivation mode
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.
readonly (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.
sharedread
(sr)
The node has write access to the disk group. Attempts to activate the
disk group for shared read and shared write access succeed. Attempts
to activate the disk group for exclusive write and read-only access
fail.
sharedwrite
(sw)
The node has neither read nor write access to the disk group. Query
operations on the disk group are permitted.
off
Table 13-2 summarizes the allowed and conflicting activation modes for shared
disk groups.
Table 13-2
Allowed and conflicting activation modes
Attempt to
activate disk
group on
another node
as...
Disk group
activated in
cluster as...
sharedwritesharedreadreadonlyexclusive-
write
FailsSucceedsFailsFailsexclusivewrite
FailsSucceedsSucceedsFailsreadonly
SucceedsSucceedsSucceedsSucceedssharedread
SucceedsSucceedsFailsFailssharedwrite
Shared disk groups can be automatically activated in a specified mode when the
disk group is created or imported. To control automatic activation of shared disk
groups, create a defaults file /etc/default/vxdg containing the following lines:
enable_activation=true
default_activation_mode=activation-mode
Administering cluster functionality (CVM)
Overview of clustering
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