split-brain recovery with crm-fence-peer script

I implemented DRBD resource level fencing with crm-fence-peer.9.sh and crm-unfence-peer.9.sh scripts on both nodes. Now, I have the following situation on my lab nodes: - both nodes otrs1 and otrs2 are online - resource are running on otrs1 - as per drbdadm status otrs1 holds the primary role and otrs2 holds the secondary role Now when I reboot otrs1 on otrs2 I get the following message: Can see that the resources are moved to otrs2: I can see the location constraint create: If the replication link becomes connected again and DRBD completes its synchronization process, then the constraint is removed. The cluster manager is now free to promote the resource. In fact the constraint is now removed: But as soon I disable the NIC on otrs2 (the currently active node) I can see the split-brain occurred: Obviously this is a split-brain scenario. Why's that so ? is it because > In case of the crm-fence-peer script it is necessary that Pacemakers > communication stays available when DRBD’s network link breaks. Source https://docs.linbit.com/docs/users-guide-9.0/#s-automatic-split-brain-recovery-configuration