6.4. Promoting and demoting resources

Manually switching a resource’s role from secondary to primary (promotion) or vice versa (demotion) is done using the following commands:

# drbdadm primary <resource>
# drbdadm secondary <resource>

In single-primary mode (DRBD’s default), any resource can be in the primary role on only one node at any given time while the connection state is Connected. Thus, issuing drbdadm primary <resource> on one node while <resource> is still in the primary role on the peer will result in an error.

A resource configured to allow dual-primary mode can be switched to the primary role on both nodes.