DRBD status :- UpToDate/Diskless

Solution 1:

This is not normal at all (everything else than UpToDate is not normal). Check if the disk you configured in the config file exists and works correctly.

From the docs:

Diskless. No local block device has been assigned to the DRBD driver. This may mean that the resource has never attached to its backing device, that it has been manually detached using drbdadm detach, or that it automatically detached after a lower-level I/O error.

Solution 2:

these commands will help you fix the problem. Run the following commands on the Diskless node.

drbdadm detach
drbdadm connect
drbdadm attach
restart the drbd service <--- this is important step