414Administering cluster functionality

Cluster initialization and configuration

When an error occurs, such as when a check on a slave fails or a node leaves the cluster, the error is returned to the utility and a message is sent to the console on the master node to identify on which node the error occurred.

vxconfigd daemon

The VxVM configuration daemon, vxconfigd, maintains the configuration of VxVM objects. It receives cluster-related instructions from the kernel. A separate copy of vxconfigd runs on each node, and these copies communicate with each other over a network. When invoked, a VxVM utility communicates with the vxconfigd daemon running on the same node; it does not attempt to connect with vxconfigd daemons on other nodes. During cluster startup, the kernel prompts vxconfigd to begin cluster operation and indicates whether it is a master node or a slave node.

When a node is initialized for cluster operation, the vxconfigd daemon is notified that the node is about to join the cluster and is provided with the following information from the cluster monitor configuration database:

■cluster ID

■node IDs

■master node ID■role of the node■network address of the vxconfigd daemon on each node (if applicable)

On the master node, the vxconfigd daemon sets up the shared configuration by importing shared disk groups, and informs the kernel when it is ready for the slave nodes to join the cluster.

On slave nodes, the vxconfigd daemon is notified when the slave node can join the cluster. When the slave node joins the cluster, the vxconfigd daemon and the VxVM kernel communicate with their counterparts on the master node to set up the shared configuration.

When a node leaves the cluster, the kernel notifies the vxconfigd daemon on all the other nodes. The master node then performs any necessary cleanup. If the master node leaves the cluster, the kernels select a new master node and the vxconfigd daemons on all nodes are notified of the choice.

The vxconfigd daemon also participates in volume reconfiguration as described in “Volume reconfiguration” on page 413.

vxconfigd daemon recovery

In a cluster, the vxconfigd daemons on the slave nodes are always connected to the vxconfigd daemon on the master node. If the vxconfigd daemon is