Objective
Recover DRBD from split brain condition (both devices set to primary) by setting either one as a secondary device.
Prerequisites
None.
Steps
Step 1: Start DRBD Service on Both Devices
On both machines, start the DRBD services using either of the following commands.
For versions below CentOS 7:
/etc/init.d/drbd start
For CentOS 7:
systemctl start drbd
Step 2: Set Secondary Device
Login to the server you want to set as secondary.
Define the server as secondary and discard the data on that server using the following commands.
drbdadm secondary all drbdadm disconnect all drbdadm -- --discard-my-data connect all
Define the other server as primary and reset the connection.
drbdadm primary all drbdadm disconnect all drbdadm connect all