# Daemon Down Node Alive (DDNA)
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Daemon Down Node Alive (DDNA) is a condition in which the VCS high availability daemon (HAD) on a node fails, but the node is running. If HAD fails, then the hashadow process tries to bring HAD up again. If the hashadow process succeeds in bringing HAD up, then the system leaves the DDNA membership and joins the regular membership.

In a DDNA condition, VCS does not have information about the state of service groups on the node. So, VCS places all service groups that were online on the affected node in the AutoDisabled state. The service groups that were online on the node cannot failover. Manual intervention is required to enable failover of AutoDisabled service groups by performing AutoEnable for the groups. Then clear resource faults if any, and bring the service groups online on another node.