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

on all affected volumes. The recovery utilities compare a crashed node's active
maps with the recovery map and make any necessary updates. Only then can the
node rejoin the cluster and resume I/O to the volume (which overwrites the active
map). During this time, other nodes can continue to perform I/O.
VxVM tracks which nodes have crashed. If multiple node recoveries are underway
in a cluster at a given time. VxVM tracks changes in the state of DRL recovery
and prevents I/O collisions.
The master node performs volatile tracking of DRL recovery map updates for each
volume, and prevents multiple utilities from changing the recovery map
simultaneously.
Administering VxVM in cluster environments
The following sections describe the administration of VxVM’s cluster functionality.
Requesting node status and discovering the master node
The vxdctl utility controls the operation of the vxconfigd volume configuration
daemon. The -c option can be used to request cluster information and to find out
which node is the master. To determine whether the vxconfigd daemon is enabled
and/or running, use the following command:
vxdctl -c mode
Table 13-6 shows the various messages that may be output according to the current
status of the cluster node.
Table 13-6
Cluster status messages
DescriptionStatus message
The node is the master.
mode: enabled:
cluster active - MASTER
master: mozart
The node is a slave.
mode: enabled:
cluster active - SLAVE
master: mozart
449Administering cluster functionality (CVM)
Administering VxVM in cluster environments