After split brain has been detected, one node will always have the resource in a
StandAlone connection state. The other might either also be in the
StandAlone state (if both nodes detected the split brain simultaneously), or in
WFConnection (if the peer tore down the connection before the other node had a chance to detect split brain).
If you get degraded Shared Storage (DRBD) you have to manually resolve split brain situation. You will need to log into Master/Slave server using SSH and connect as root.
On Master (primary) server :
[note color=#ddd]drbdadm connect all [/note]
On Backup (secondary) server :
[note color=#ddd]drbdadm invalidate all
drbdadm connect all[/note]
Upon connection, your split brain victim immediately changes its connection state to
SyncTarget, and has its modifications overwritten by the remaining primary node.